Aust. Red Cedar - fine sanding issues - help please! :-)

[deldridg]

Hi all,

after many dozens of hours working on our cot (baby is due Apr 4), finally I'm down to the fine sanding of each component before oiling (Organoil Danish Oil) and assembly.

Here is my sanding process:

- random orbital with 80 grain to remove and large marks if present (saw marks etc.),
- random orbital with 240 grain to smooth above finish,
- hand sand with 240 along grain,
- lightly chamfer edges with block plane and round with 240 grain (by hand)
- hand sand with 400, then 800, then 1200 (then take a cold one out of the fridge!!).

Me being relatively new at all this are proceeding as above with every piece (there are dozens!) and on a few pieces have found that when sanding with the finer grains, sometimes a fine piece of grain will tear out of the face leaving a groove which then requires further heavy sanding, depending on depth (sometimes 0.5mm). Horrible stuff!

This has only happened about 4 or 5 times, but it's enough to scare me - especially with the very large outside faces (panels etc.). So far nothing catastrophic, touch wood...

All in all, the hours and slog are completely satisfying, though I can't help but wonder if there are more efficient ways to reach the same quality of finish. Oz Red is to die for (at least financially) and so I'm doing my level best to bring up the best finish possible. Our baby deserves a decent cot IMHO! )

Any tips on avoiding this random tearout (and perhaps on improving the oil finish ~ ie. light sand with 1200 between coats perhaps??) would be greatly appreciated!

Many thanks,
David E (Sydney)

[DJ’s Timber]

I think you're starting at too low a grit especially if it's Cedar and also too much of a jump from 80# to 240#, I'd start at 120# then 150#, 180# before you get to 240#.

The 240# straight after 80# means that it has to work harder and by working harder the timber gets hot, which might be causing your problem.

Same for the higher grits, should also be a 600# and 1000# in between as well.

[deldridg]

Hi DJ (I'm a DJ ~ "David John"...),

thanks very much for your kindly advice. I'm sure you're right but with my limited knowledge and resources, I found the orbital + 80 grain to be effective at eliminating serious marks in the timber from its original cuts without taking a whole day! Patience is certainly something I'm learning however!

I have certainly noticed that more than other timbers, A.R.Cedar certainly gets hot under sanding and so perhaps that is a contributing factor to the problem. I will address this in future sanding efforts (of which there will be plenty in the coming weeks!!).

Cheers,
David

[Sebastiaan56]

It may also be useful to use something like shellac or a varnish to seal the surface before sanding and give it more rigidity. On a box I made I actually sealed with epoxy first before commencing the sanding through the grits, came up a treat. The Aust Cedar I have is very soft and easily damaged.

[rsser]

Yes.

The stuff is soft and cheap 80 grit can leave deep scratches.

At a min you must not skip a grit as DJ points out.

[deldridg]

Thank you all for your help. Building this cot has so far been a great learning curve, even though the staggering amount of sanding/work involved has sometimes been a little daunting. A bit left for me to do yet though!

My wife commented that I may have to exercise some control when the new little one disgraces him/herself all over this structure... I'll cross that bridge when I get to it!

Cheers and thanks again,
David E (Sydney)

[rsser]

A bit of teething rusk smeared over the wood should make a decent grain filler!

Good luck with both newborns ;-}

[deldridg]

No why hadn't I thought of that??!! )

Cheers and I hope little Eldridge is less work than his/her cot! He/she had better appreciate all that hard work and treat it with respect...