kitchen solid bench top corner problem.

[JDarvall]

Another issue concerning the kitchen I was hoping to discuss.

The plan is to have a blue gum bench top 600mm off the wall.....

Going to make it up out of 1 1/2 x 8" boards.....Corners a problem as you'd all know.....and I shouldn't even bother mitring it.

Mentioned it to me boss, and he agreed saying to just butt it. But I think that looks like caveman stuff.

So, I was playing with the idea (don't laugh) of edge joining some of the offcuts like in the sketch, so it looks right....and cut it curved (the latest thing she wants).

So we're looking at 1200 wide before it hits the oven ? .....You reakon I can control that kind of movement in kiln dried blue gum ? :-

[m2c1Iw]

So we're looking at 1200 wide before it hits the oven ? .....You reakon I can control that kind of movement in kiln dried blue gum ? :-

Yep, with a veneered torson box D

[Pusser]

http://www.tastimber.tas.gov.au/Species/pdfs/Bluegum.pdf shows movement between 5 and 25% moisture Content as 049% radial and 061% tangential for each 1 % channge in moisture content. That is 5.8mm for 1200 mm of quatersawn or 7.3mm for flatsawn. You will need to seal it well to minimise changes in moisture content. It will dry out qhicker near the oven of course and tend to shrink. Don't know if this is much help but it does give you an idea of total movement.

[JDarvall]

Ta. Too late on the torsion box.

Thinking just pin it well to the wall side, and let it slide enough through screws.

Its a darker species of blue gum I think.

[m2c1Iw]

Just kidding with the torsion box crack. I assume the 1200 section is against a wall? What about a dovetailed or breadboard style trim piece attached to the wall could make it slightly proud bit of rounding and it might allow for movement and give a nice finish, perhaps continue all around the edge. hope you understand what I'm getting at.

Cheers Mike

[JDarvall]

I wasn't shore if you were kidding . Had me going. started googling for 'kitchen torsion box' you did. :D

think I know what you mean about the breadboard....trying to keep it flat, whilst letting it move, you mean. I'm not sure if thats necessary or not.

I suppose it all depends on how much the wood wants to cup.

[JDarvall]

Hang on. I might checkout the other links below as well (to add to my confusion :D)

[m2c1Iw]

Hmmm...6-7mm of movement over 1200 thats a lot to contend with. I wonder how much moisture variation you would expect in a kitchen. I think you need better advice than I can give:-. Good luck

[JDarvall]

I don't know. Sounds like you probably know more about it than me mate. Good to get input from others. Appreciate it.

I've built a few tables before. But this is my first kitchen with solid tops.

[Harry72]

Id make up a corner piece using 2 x 22.5° mitres, the wood will "flow" around the corner.
Its what I've done for my kitchen.(a WIP)

[JDarvall]

ta Harry. I'll have a look for your WIP

[JDarvall]

I can't find it. But are your saying both your benches are cut at mitres? Then you've got 2 x 22.5 mitres in between?...epoxied up ?. Wondering how wide and thick your bench is. And what timber.

[JDarvall]

Actually, now thinking I could get away with mitring it, because its just a small ajoining piece. Heavily joint this mitre with deep tongues and epoxy, and just let this small piece (600mm of it) move off the wall, so the mitre doesn't open up. Cover any gaps that appear at the wall with moulding. What do you think ?

[jmk89]

Jake

How about a pattern based on parquet flooring? I have attached a picture before rounding of the corner.

[JDarvall]

Maybe. Thanks Jeremy.

[bitingmidge]

NO! :oo:

You'll have movement issues in two directions, and at every intersection! Sorry Jeremy, it'll just blow itself apart!

P
:)

[JDarvall]

So what do you think I should do ? Well, what would you do ? :)

[DJ’s Timber]

Why not just have the one join at 45degs with some bench joiners under it?

[JDarvall]

whats a bench joiner ?

If its hardware to stop movement I think that be futile. Somethings going to give it wants to move I'd say. Just my opinion though.

Thinking about this next :rolleyes:...

avoiding it alltogether, abandon a curving corner (unfortunately) and just butt everything with the very corner being a square of tiles. She could put hot pans straight on it from the stove. Nice pretty tiles with flowers on them or something.

It all starts to look squarish though I think. Bad feng shoe.

[JDarvall]

Oh , you mean just tie it together with screws and sticks.

[DJ’s Timber]

Bench top connectors (http://www.nover.com.au/productinfo.asp?ID=572)

Still want to know why you're not considering 45deg join

[JDarvall]

I see. I'll have to remember them.

I'm just worried about a gap forming at the mitre. I think that looks horrible. And the wider the timber the more likely its too occur.....and 600's pretty wide.

[bitingmidge]

So what do you think I should do ? Well, what would you do ? :)

I'd laminate it round the corner in concentric curves! :wink:

Nah,

I'd replan the kitchen so the bench didn't go round the corner. Either move the stove against it (bad, bad, bad) or put a corner appliance cupboard of some description to hide most of the join.

There are three options as far as I can see:

Mitre (which I don't like)

Butt (which I don't like)

Or do a square in the corner with the boards at 45° and butt both directions to it if that makes sense.

It might be nice to drop a couple of brass strips in at the joins to trim them. It's an old trick I used to use with Granite-look laminex to make it look more like granite! :wink:

Cheers,

P
:D

[m2c1Iw]

Jake,
I like your first idea with the curve. Looking at that design if the bench top sits on the cupboards using heavy dowel in slots that overcomes the 7mm odd movement. Then the issue is top to wall, what did you have in mind for a splash back as long as it is not attached to top no probs!!!

I am having trouble with 7mm for every 1% MC over 1200mm is that right do you think and if you start with well season timber how much change will you get. I dunno.
Mike

[JDarvall]

Ta midge. It just I don't really want to do something boring.

And she seems to be sold on the idea of it curving around (as in that first picture at the start of the thread)

So, you don't think that origional idea would work (1200 wide) ? ...I know its very wide but if the tops held down with skews in slots allow movement,,,,and since it can move towards/away from the oven ...then I thought it be ok. but I haven't done it before.

[martrix]

Agree with DJ. Mitre it and use silicone and bench top joiners in the mitre. They are strong and you wont have a gap open up. When you fix down the benchtop, allow for movement with your fixings as normal.

Doing it your original way would look bad IMHO with all of the endgrain showing.

[JDarvall]

Don't really know how much it'll move Mike. But I figure, if I make the slots that take the hold down screws way bigger than any kind of movement I could get, I suppose it doesn't matter.

What I don't know about though is cupping. That may start ripping the carcass apart. I was going to use face frames on ply. So maybe worth while re-enforcing that area ???? don't know really.


Jake,
I like your first idea with the curve. Looking at that design if the bench top sits on the cupboards using heavy dowel in slots that overcomes the 7mm odd movement. Then the issue is top to wall, what did you have in mind for a splash back as long as it is not attached to top no probs!!!



yep. Thats the only real issue I was thinking too.

Need something clever, that handles the movement but keeps a seal.

thinking..
Some kind of lip at the end of the top, thats covered by moulding
or...some kind of rubber compression going on.
or a sign to remind her to not spill anything there.

might be clever hardware out there to do this ?

[JDarvall]

Agree with DJ. Mitre it and use silicone and bench top joiners in the mitre. They are strong and you wont have a gap open up. When you fix down the benchtop, allow for movement with your fixings as normal.

In practise have you noticed this will work ok ?........

I'm just still concerned because, as I picture it, if the timber around the mitre wants to shrink, that mitre will want to open up. But if it can't because of those bench joiners, then it'll try and release the tension somewhere else won't it ?....Could mean it'll cup, or a split the timber. Maybe ?

But, then thinking now it shouldn't be a problem if its free to move of the wall off that small top side (oven side).



Doing it your original way would look bad IMHO with all of the endgrain showing.

Good point.

[JDarvall]

yep. sold me . Thanks fellas. I'll mitre it with bench joiners with plenty of room for movement and seal the oven side of the top with a lip and moulding (that lip should be easy enough since I'll be running with the grain there)

And that way I'll be able to keep my curved corner !

appreciate everyones help. :2tsup:

I think I wouldn't do it though if I had two long bench tops running to a mitre

[martrix]

yes, seen it done a fair few times.

This taken from here.http://www.thors.com.au/category.php?id=27


Mitre joins are usually the best way of joining bench tops. Mitre joins can be glued as the grain direction and movement is equal across the joint.

[martrix]

Our method of installing a join in a bench top was to also have a few biscuits to help keep things flush.

So a bit of yellow glue in the biscuits and silicon on the rest, then clamp it all together with the bench top connectors....very strong and reliable., and yes you can still have your curve.

[JDarvall]

You sound very confident Matrix. Glad someone is.

Just heard of some disaster stories in the past.

I'll just blame you eh if it all ????s up. :p:wink:

[JDarvall]

But as I said above, probably talking to an experienced cabinet maker is the way to go on this, too much effort to waste on a simple error.

:? well, My boss is an expert cabinetmaker (no doubt about it from his work), and he says its not worth risking and to just butt it.

Theres just so many opinions, and experences. Maybe I should have just gone for the man made shyt afterall. Bit too late now. Timbers on its way.
This is where its coming from if interested. http://solardry.com.au/

What product do you blokes think I should finish the top with ?

[martrix]

You sound very confident Matrix. Glad someone is.

Just heard of some disaster stories in the past.

I'll just blame you eh if it all ????s up. :p:wink:

No worries, you're a whole state away.:D

The disaster stories are probably because the process was done incorrectly.

Here is some reading for you.

http://www.dgi.com.au/bench1.html


http://www.dgi.com.au/images/proj10.jpg

[Harry72]

I can't find it. But are your saying both your benches are cut at mitres? Then you've got 2 x 22.5 mitres in between?...epoxied up ?. Wondering how wide and thick your bench is. And what timber.

Na its not on here as a WIP thread... its a current WIP!

Its 650mm wide by 40mm thick jarrah 8m in length in a U shape, the two corner piece's have a 22.5° on each side so the 2 pieces on each side still are square shaped slabs. Shaping the corners and scribing(made up templates)to the wall is proving to be tricky but it should look real nice when finished.
There will be no glue... it would be impossible to move a top of this size if you glued them up, I guess it would weigh about 300kg:D, the corners will be held together by zip bolts.http://elraco.com.au/images/KDZ10100.jpg

Available from Ray at Elraco's (http://elraco.com.au/product_info.php?products_id=5162)

[JDarvall]

ta. That mitre looks nice. (matrix)

So what would you do with my splashback ?

How much of a gap between the bench top and the wall ?...2mm or something.

Tiles come down, and how would you seal it ?

Just got to get my head around whats 'good enough'. I don't want that seal cracking from some kind of movement. uno.

[DJ’s Timber]

How much of a gap between the bench top and the wall ?...2mm or something.

Tiles come down, and how would you seal it ?



No more then 2mm, got to allow for shrinkage.

Leave tiles 2-3mm short of bench and use a flexible sealant, like coloured silicone.

[martrix]

No more then 2mm, got to allow for shrinkage.

Leave tiles 2-3mm short of bench and use a flexible sealant, like coloured silicone.

yep, what DJ said. The tiles will probably end up being around 10-15mm off the wall so I would aim for around a 5mm gap from the benchtop edge to the wall. Also means its easier to fit if your walls are badly out (less material to remove from the back edges of the top).

A good flexible sealant will move with the timber.

[JDarvall]

Na its not on here as a WIP thread... its a current WIP!

Its 650mm wide by 40mm thick jarrah 8m in length in a U shape, the two corner piece's have a 22.5° on each side so the 2 pieces on each side still are square shaped slabs. Shaping the corners and scribing(made up templates)to the wall is proving to be tricky but it should look real nice when finished.
There will be no glue... it would be impossible to move a top of this size if you glued them up, I guess it would weigh about 300kg:D, the corners will be held together by zip bolts.http://elraco.com.au/images/KDZ10100.jpg

Available from Ray at Elraco's (http://elraco.com.au/product_info.php?products_id=5162)

yeh, sounds kinda heavy. I bust my guts lifting 300x50x5000's kwila planks on the saw with another bloke....so that lift sounds like 4 blokes at least eh. you can keep that. Goodluck with it.

And with your previous mitred jobs. No complaints ?

[Harry72]

" And with your previous mitred jobs. No complaints ?"
Errr nope... this is my 1st and only ever kitchen, I dont intend to make another kitchen so long as I live... I'll make the doors for people but thats about it!

I got 5 commissions in the pipe line waiting because of this dam kitchen:(

[JDarvall]

:2tsup: thanks guys.

One last question. sorry.:-.... what finish would you use on the bench top....and does one coat on the underside and 3 coats topside sound good ?

Thinking of something pretty hardy. Something she can put hot pots on maybe.

[Bleedin Thumb]

I used 3 -4 coats of Cabots poly Gel to avoid drips. I actually cheated and used weathershield paint underneath ( allowing for the overhang of cource) because it dried quicker.
After 3 years its scratched... but I think I will leave it another year befor doing another coat.
FWIW go the mitred corner with connectors under. Becareful with the connectors its a fine balance between not tight enough and splitting the timber. You should also make sure that your cut out for the sink is 200mm min away from the mitre.


I used these connectors because of the speed but the drawback is the plastic threads burr a bit when you are trying to get some good tension.

http://www.lincolnsentry.com.au/Product.aspx?id=571

[juan]

Caeserstone is sounding better all the time

[JDarvall]

I used 3 -4 coats of Cabots poly Gel to avoid drips. I actually cheated and used weathershield paint underneath ( allowing for the overhang of cource) because it dried quicker.
After 3 years its scratched... but I think I will leave it another year befor doing another coat.

Ta mate. whatever I put on, I'm thinking of just spraying it on. Got a compressor now. Can you put hot pots straight on it ?...Want something really hardy uno.



FWIW go the mitred corner with connectors under. Becareful with the connectors its a fine balance between not tight enough and splitting the timber.

:rolleyes:...:D...I wonder if the whole process (just quietly) is considered acceptable, because its convienient for the cabinetmaker to do it this way ? ....I'm just still a bit worried about these mitres. I know its considered ok by the pro's and I'll do it, but the principle still worries me. Especially after I've got a really nice finish down on top all I need is 1/2mil gap to appear and it'll look shyt. who knows.



I used these connectors because of the speed but the drawback is the plastic threads burr a bit when you are trying to get some good tension.

http://www.lincolnsentry.com.au/Product.aspx?id=571
I thought they looked a little plasticty too...bit too clever. Didn't mention it to spare Harrys feelings (sniff) :p:wink:...Maybe Harries better at using them. But I'm guessing that Jarrahs weight will dictate things. Trying to get the other ones DJ showed earilier.

[DJ’s Timber]

If you can't get any of the ones I showed you, I can post some up to you. Got a few spares laying around, they even come in a bag with 3 in it including the biscuits. Just PM your address and they're yours.

Another alternative is to cut some thread rod to length and use washers and nuts after you've squared one side of the hole.

[Harry72]

AT those zip bolts dont have plastic threads they are metal and very fine guage threaded... super tight using very little pressure!
They have a chuck key like a drill chuck to be done up with a cordless drill... zipped up:)

[Bleedin Thumb]

Ta mate. whatever I put on, I'm thinking of just spraying it on. Got a compressor now. Can you put hot pots straight on it ?...Want something really hardy uno.


:rolleyes:...:D...I wonder if the whole process (just quietly) is considered acceptable, because its convienient for the cabinetmaker to do it this way ? ....I'm just still a bit worried about these mitres. I know its considered ok by the pro's and I'll do it, but the principle still worries me. Especially after I've got a really nice finish down on top all I need is 1/2mil gap to appear and it'll look shyt. who knows.


I recon its the only way to go, considering that the timber expands differentially. As far as the gap goes when I was cutting mine with a small maketa I frupped up as the blade wasn't set correctly to 90 deg:((:((:(( anyway i do have a gap that goes from 0 -.1mm. :doh: I can't do much about it except drink copious quantities of alcohol so I don't notice it.:)

BTW I don't think there is a finish (for timber) that allows hot pots going on.

[Eli]

BTW I don't think there is a finish (for timber) that allows hot pots going on.


None I've heard of, if you're not counting finishing the job by insetting a tile in the surface.:roll:

[JDarvall]

If you can't get any of the ones I showed you, I can post some up to you. Got a few spares laying around, they even come in a bag with 3 in it including the biscuits. Just PM your address and they're yours.
.

Thankyou Kindly. I'll try and get them first. Else, I'd appreciate that. Try and find something I can do in return.

[JDarvall]

I recon its the only way to go, considering that the timber expands differentially. As far as the gap goes when I was cutting mine with a small maketa I frupped up as the blade wasn't set correctly to 90 deg:((:((:(( anyway i do have a gap that goes from 0 -.1mm. :doh: I can't do much about it except drink copious quantities of alcohol so I don't notice it.:)

Frustrating. I'll have to do it that way too.



BTW I don't think there is a finish (for timber) that allows hot pots going on.


Probably right. Just remember reading somewhere some product that claimed you could. If it exists, probably cost too much anyway.

[Bleedin Thumb]

Sorry Harry I didn't see your response about the Zip Bolts.
They must have changed then to metal (for the reasons I mentioned) after I had bought mine.

[Gaza]

DGI whos website was posted in this thread sell there 2 pac finsh for timber bench tops, not 100% sure if it will take a red hot pot but it does take a fair amount of abusing.

I have also seen that wet glass epoxy used but it was clear coated with poly over the top to protect it from being damaged. That was for a commerical bar application.

[JDarvall]

thanks. that'll do me.

says....

<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0><TBODY><TR vAlign=top><TD width=160>Heat Stability </TD><TD>Unaffected by boiling water or heated plates and is heat stable to approx. 400°F (200°C)</TD></TR></TBODY></TABLE>

:2tsup:

[GraemeCook]

I did an L-shaped kitchen benchtop about 15 years ago from 8 x 1 1/2 inch (Tasmanian) celery top pine. The join was mitred and there were loose tongues glued between the planks. I was not satisfied with the mitre - I didn't cut it accurately enough - so I routed a half inch trench over that join and epoxied in a batten. The bench was then sanded and given six coats of two-pot polyurethane on ALL surfaces. Light rub-down and two more coats every five years or so. Looks great and there have been no problems.

Nextdoor neighbour had a blackwood butcher block bench top professionally installed at same time at exorbitant cost. It cracked in about six weeks, was repaired many times and replaced twice. After about five years he had it replaced with a corian benchtop, and still loves it.

Not definitive, but food for thought.... or more confusion.

Cheers

[JDarvall]

Sounds like its not all about who does the work either. That even if you do the right thing it might still crack on you. Dependent on what the wood wants to do I guess.

I wonder if blackwood has a bad rep for this sort application.

[echnidna]

blacxkwood is regarded as a stable timber Jake

[JDarvall]

ta Bob.

[Bleedin Thumb]

... so I routed a half inch trench over that join and epoxied in a batten.



That's a great idea! you could even use a contrasting coloured timber..could look quite classy.


Any tips that can be used to hide my poor workmanship are always appreciated.:D

[JDarvall]

Be good too to hide cracks should they appear later too.. Won't be able to run the router all the way to the edge of bench though due to the wall....chisel out that little bit by hand I spose. oh well. see what happens.

[JDarvall]

the boss still insists to dump the full mitre idea all together cause of potential movement problems.. Says butt, and mason mitre it to continue a edge profile around corners. Makes me wonder why that link provided above said its not recommended to use them ? ...

[DJ’s Timber]

I'm interested to know how many timber bench tops your boss done using a mason mitre? Can you go and see any that he may have done and how have they held up?

I have done a few bench tops using a full mitre and haven't received any callbacks yet and this includes laminated and full width slabs.

Ask around and see if there is any locals with timber tops and if you can get permission to see them to give you an idea of what has held up and what hasn't.

[JDarvall]

Sorry, I'm probably going on about it too much. Just can't really afford to stuff it up.

I get fridays off. So, I'll ask him monday.

He's visualising it, like I did initially, that any movement will open it up.

At smoko yesterday I brought it up again, and from what I gathered, his idea was to epoxy up just around the mitre (mason mitre) and let the rest of it float towards the wall. But that made me question him on there being too much movement at the wall for the seal. ???

Seems to be two lines of thought on this one. anyway.

[arms]

ahh the idea ,worries me greatly when people think about what to do and then ask someone who tells them that this is the way that they would do it ,then the someone takes the advice on board ,then when it may or does go wrong they say well you should have made your own decision.
coat all exposed esges with whatever finish you are going to use ,do not do this sparingly as you will be sorry,timber tops for for that matter anything timber HAS to be allowed room to move ,to not do so is to your own waste of money

[JDarvall]

Want to say, I am appreciative of all the ideas. I won't be blaming anyone, except myself should it stuff up.

Wondering what would you do Tom ? ....big butt joint, mason mitre, or just a big mitre at the corner. Sounding like you'd prefer to just butt it (?)

[journeyman Mick]

Jake,
I love working with timber but I don't generally recomend timber kitchen tops to my clients for a couple of reasons.
1. It's quicker and easier to get the job done and the cheque in my hand using pretty much any material other than timber.
2. Cross grain joint problems/expansion/contraction issues.

I won't mitre the corner joins - ever. Relative humidity here swings from 100% in the wet season down to about 20% in winter. There's a lot of potential for movement.

Did a "L" shaped timber top not too long ago. It was a butt joint with biscuits to align it and metal benchtop connectors to pull it together. The cut outs for the connectors were made with elongated openings to allow for movement. The first piece was fitted to the cabinets, screwed from underneath with the screw holes at the front of the cabinet elongated to allow for movement from back to front, which is pretty standard.

The second piece was then fitted and pulled up tight with the metal connectors (after all surfaces had been coated, of course). The holes in the cabinet for this piece had to allow for movemet of this piece (back to front of cabinet) but also had to allow for the movement of the other piece (along the grain of this piece). So all the holes were drilled hugely oversized and screws went through a piece of ply as a washer. Our wet season has started and they've had no problems and I don't anticipate any.

I hope my explanation has been clear enough, some diagrams would probably be helpful but I can't drive any of the drawing programs and my scanner is buried under a pile of paperwork.:-

Mick

[arms]

Want to say, I am appreciative of all the ideas. I won't be blaming anyone, except myself should it stuff up.

Wondering what would you do Tom ? ....big butt joint, mason mitre, or just a big mitre at the corner. Sounding like you'd prefer to just butt it (?)


what mick has said is correct ,butt joint ,elongate holes ,oversize washers ,this is the industries recommendation so i would recommend you go with the people that know what to do and are willing to share their knowledge with you

[Dirty Doogie]

HI Jake,

I have been watching this thread and your kitchen querie since it started but havent posted becuase my experiences with making a hardwood kitchen benchtop have been largely negative or at least a trial.

I don't want to say don't do it becuase if it works a Blue Gum benchtop is a beautiful thing. All I will do is recount my experience.

About 15 years I made a kitchen for some friends. In the design stage it was decided that the benchtop would be made from some old dressed blue gum boards my friends father had been keeping under his house for 30 years. The boards were machine dressed to 140 wide x 32 thick and had been kept very straight, dry and clean. The timber had been back sawn.

I glued and dowelled 5 boards together using Resorcinol making sure the radial grain alternated on adjioning boards. The benchtop was L shaped 2100 x 2700 and I put a mitred corner and used benchtop jioners (bolt type). The corner was total PITA and had to machine planed and sanded to get the boards level with each other.

Before installing the benchtop I sealled the underside and end grain with polyurethane clear finish and the top was finished with a non yellow Poppyseed oil (from artists suppliers) and polished to a satin sheen.

Now to this day I really dont know what happened or why - but 6 months later - cracks began developping in centre of the boards and ran from end to end AND the mitre opened up. The splitting continued over the next summer. At first I went over and filled the cracks and refinished - but was very disappointed as was the friend.

Finally it was decided to replace the homemade benchtop with a factory made timber top. At the time Hyne timbers made red color select grade hardwood laminated benchtops and my friend spent $1800 on a new 35 mm thick top.

The timber expert at Hyne told me that the problem was probably that my pieces of timber were too wide and generated too much movement according to humidity. And that stable benchtops needed quarter sawn material cut down to a square or almost square shape - seasoned of course and glued hot .

I have never tried a 30mm thick + hardwood timber benchtop again - but the laminated benchtop from hyne's is still flawless ( well last time I saw it 3 years ago).

I have since then made a red gum benchtop from 15 mm thick x 120 mm wide boards glued to 32mm MR fibreboard without any problems ( including mitre)

So that is my experience - hope your bench is better behaved.

Doog

[journeyman Mick]

Doog,
what a bugger! Can you recall if the cracks were only in the top face or if they ran right through the boards top to bottom? I'm wondering if the problem may have been caused, at least in part, by there being different finishes top and bottom. I'm not familiar with poppyseed oil at all but I'm guessing it was able to absorb more moisture than the polyurethane and it certainly would have been exposed to more moisture as the top face. That said, I can't understand the cracking, one would expect a cupping or bowing.

Mick

[Dirty Doogie]

HI Mick - over the years I have wondered the same thing about the oil - the cracks started out as fine fissures on the top surface but by the end of the first summer had gone about 30% the way down and had actually gone all the way through at the mitred corner.

Poppyseed oil is a hard finish oil that they used to make artists oil paint and old fashioned white house enamel from, especially light colors becuase it doesnt yellow. I have used it on other moisture senstive timber like hoop pine without any problems.

The way I look at things - if something doesnt work but you've learnt something (even if it is to never try it again) then it hasnt been wasted time LOL

[JDarvall]

I was wondering Doog, .......How did you fastern the bench to the frame ? Did you have it so the wood could move freely around the fasterners ? Thinking that may explain it.

Sorry to bring up questions about something you probably want to forget.

[journeyman Mick]

Doog,
my guess is that even though the timber was well seasoned it's moisture content was greater than the environment in which it was eventually fitted. The poly would have been close to impervious to moisture, at least compared to the oil. So the top surface started drying out whilst the timber below stayed where it was. The timber below didn't allow the top surface to move so small fissures opened up. As these fissures opened up they allowed more timber to dry out, but the bottom face was still impervious and unmoving. This resulted in major cracking. The mitre would have opened up regardless of the finish. As the timber expands or contracts the angles at the end of each piece change so that they're no longer at a true 45 deg. resulting in a dodgy mitre. Be interesting to see if anyone else has any other explanations for this failure.

Mick

[Dirty Doogie]

Hi Jake - the carcasses were MR chipboard and the bench top was fixed to the cabinet sides by 35 x 35 x 150 long angle brackets screwed on. As I rememebr there were only 4 or 5 of these brackets for the whole job. The brackets were fixed mainly under the centre plank of the benchtop leaving the other planks to move around.


Hi Mick - I would have thought that the humidity in the kitchen would have been quite high and the first summer was very wet. Perhaps it was due to some difference in "breathabilty" caused by different surface finishes that did it. Never the less I have never seen hardwood crack like this before - even in structural work where stresses would be much greater.

AS it turned out I cannibalised the old blue gum top and made some sliding timber window frames out of it without any great problems.

The 2 or 3 timber bench surfaces I have made since then by laminating thinner timber onto man made board, using good old sikaflex, have worked perfectly with difficult timbers, RED GUM and Northern Scribbly Gum (E. signata).

[JDarvall]

. As the timber expands or contracts the angles at the end of each piece change so that they're no longer at a true 45 deg. resulting in a dodgy mitre.

Thats it in a nutshell I origionally thought...all mitres seem subjected to this. Sounds like your probably right about it being a worry due to the moisture swing here.

Thanks doogie for the explaination and everybody else.

So i wont be mitring it. Seriously considering not having a solid bench top now at all. I don't like butted slabs. Sounding like dramas. Might use the blue gum for something else. :?:?:D

[Dirty Doogie]

I didn't mean to put you off the idea Jake!

I think the timber guy from Hynes may have been on the right track though - my boards were too wide and/or thick and the grain travelled the wrong way through the boards. When they boards wanted to move the edges were stuck rock solid so stresses built up along the center.

Why not try the benchtop with narrower sections? I always meant to try it that way myself - but never got around to it.

Maybe not have a corner return section ?

[juan]

Great discussion guys. You have helped me decide on my new kitchen benchtops. Caeserstone or granite.

[Dirty Doogie]

LOL Juan !! Timber benchtops do work - but of those that I have seen and dont have problems are all made from narrower strips of timber - or a single slab.

[JDarvall]

LOL Juan !! Timber benchtops do work - but of those that I have seen and dont have problems are all made from narrower strips of timber - or a single slab.

:D honestly, who knows ! ....

Just quietly though, the misses and I had a talk about granite too last night....or some kind of heat resistant laminate. (And just keep the bluegum for myself :2tsup:)

..and this site as well.
http://www.granitetransformations.com.au/home.html
Some kind of thin stuff to put over existing benchtops. Was wondering, maybe I could make the frame and just put a benchtop out of chipwood on top (or something cheap that works)and just get those blokes to come in and put this wizebang stuff on for me.....

I asked them how much, but no response. :~ I get that a lot from these places. Why do they advertise themselves on the internet, and not respond to potential customers. I'm pretty shore I wasn't rude in my query. :?

[echnidna]

I have made many tables.
I won't use over 140mm wide boards but I really prefer using 70-90mm wide boards.
Never had a movement problem with the narrow boards.

btw you can get stone look laminates readily