polyeurothane PITA

[mattym83]

any body got any secrets for working with polyeurothane
i have found that if i put a thin coat on i get paint brush stroaks
if i go over and add a secong coat like 2 mins later the first coat seams to have partially dried and when the second coat applies i seams to get bubbles from the first application
i thought about spraying it on but the cost of the sprayer is not worth it

any help would be great

Matt

[Woodwould]

What do the instructions on the side of the tin say to do? If you've followed the instructions, give it a chance to level out and dry. You may be required to lightly sand between coats, but only after the first one has dried.

[mattym83]

well i have followed the instructions but i dont expect it do start to dry in 2 mins it does level out to a certain degree but still leaves some lumps

[Chipman]

Hi Matty

Assuming you have a good timber finish (sanded at least to 240 better 320) It is good to damp the surface off and then sand again when dry.

With polyurethane, it is important to:

1. use a good quality brush
2. give a good liberal coat and brush it evenly right from the start. DO NOT over work it.
3. don't give too heavier a coat either. If you are having trouble, you could thin it with a little turps if oil based polyurethane.
4. NEVER go back over it later, you will stuff it up for sure.
5. If there is something wrong, leave it to dry out and after one or two days use 400 wet and dry paper to sand it out using a water with a little detergent in it.
6. Generally, 3 coats should be enough (make sure you sand between coats)
7. Don't use it in an overheated place...it will dry even faster and make the problem you are having worse.

A better suggestion if you are having troubles, you should try wipe on poly (MINWAX) available from Bunnings. Some brush on the first coat and then use a lint free cloth to wipe on the next couple of coats and you can get a fantastic finish. (The other alternative is to buy a compressor and spray gun which are quite reasonably priced)

Here is a box finished in wipe on polyurethane (no brushing or spraying)


I hope this helps...Hang in there, you will master it!

Chipman

[RufflyRustic]

I can only second what Chipman has said about Minimax Wipe on Poly. Brilliant stuff and so easy to apply.

cheers
Wendy

[spokeshave]

I raise a third hand to Wipe-on-Poly. Top stuff.

Steven.

[stephenjay]

Hey Matt,

I have been using Minwax Wipe on Poly for many years and it has never failed. Never use oil based stain prior to applying it as it will be guaranteed to streak.
I wait minimum 12 hours brtween coats. I usually use an Abralon pad 500 grit between coats with a random orbital sander on low speed.

Good luck

[Chipman]

Stephen,

Just an observation...you CAN use oil based stain under oil based polyurethane..... only requirement is that you MUST make sure you wipe the stain down thoroughly after application with a clean soft cloth to get all the excess off and leave it for a minimum of 24 hours (depending on the weather) to completely dry. The box 3 posts up was done that way as is most of my furniture and projects. If you want to get a really great finish... burnish the oil based stain in by sanding it in with 320/400 grit paper....messy but nice. (Probably better to use a filler...less messy.)

If you are in more of a hurry, use a water based stain and it will dry faster and never run with oil based finishes. Only issue here is the swelling of the grain...you have to dampen the surface down several times and sand again when dry before staining. Even many dye stains will run/streak under poly or lacquer if the excess is not thoroughly removed, even if left several days... (see this at school with student finished work all the time)

Certainly if the application of an oil based stain under wipe on poly is not done correctly, you will get streaking exactly like you say....

Cheers,
Chipman

[Bluesy]

I was looking at minwax wipe-on ploy in Bunnings the other day (considering it for a guitar finish). How clear is it? I don't want to darken the wood (New Guinea Rosewood) too much.

[Pusser]

August issue of popular woodworking has a good article "The 7 myths of Polyurethane" by Bob Flexne. Worth a read - it is the current issue in the newsstands.