Thread: Plexiglas as a timber stabiliser

Don't know anything about its use as a finish, but I remember using acrylic and acetone to make a glue for building model aeroplanes 60 or so years ago. It worked very well and it was a lot cheaper than buying a tube of glue when pocket money was a bit thin on the ground.

Plexiglas is methyl methacrylate fiberglass resin, used, as you know, in boat hull and deck construction.
If you go that route, outgassing the resin is a chore to prevent bubbles.

What is the point of "stablizing" timber?
For totally dead stuff, temperature or humidity changes and wood moves.
There's nothing with a zero coefficient of expansion.

Originally Posted by Robson Valley

Plexiglas is methyl methacrylate fiberglass resin, used, as you know, in boat hull and deck construction.
If you go that route, outgassing the resin is a chore to prevent bubbles.

What is the point of "stablizing" timber?
For totally dead stuff, temperature or humidity changes and wood moves.
There's nothing with a zero coefficient of expansion.

I was intrigued more with the overall notion than anything else. Good lateral thinking.

Not stabilising timber to stop expansion/contraction, but stabilising punky wood for turning. Possibly also to settle end-grain a bit. In this type of application, a few bubbles wouldn't hurt, if 'outgassing' is a potential drawback. Maybe coat/soak the timber then wrap it to slow evaporation and allow the bubbles to escape?

Glue, as mentioned, is another good use. (Thanks safari)

Probably others not yet thought of.....

You could just use the stabilising resin that pen turners use - longer working time (needs heat to cure) so you can vacuum out all the bubbles.
http://www.timberbits.com/cactus-juice

Originally Posted by Master Splinter

You could just use the stabilising resin that pen turners use - longer working time (needs heat to cure) so you can vacuum out all the bubbles.
http://www.timberbits.com/cactus-juice

Definitely, and no doubt get a better result, if you have some on hand and a vacuum setup to suck out the bubbles. OK if you're doing it regularly, but for a one-off, expensive. I've heard of Cactus Juice but never tried it. (I don't make pens.)

The idea of recycling all my scraps of acrylic sheet left over from various projects appeals too. As a quick-fix wood hardener, I reckon this would do as well as, or better than, my MinWax stuff, if it's thin enough to soak in well.

I don't actually have a 'punky' problem, (love that word), the video just got me thinking.

I'm almost out of acetone, but when I get another bottle in a couple of days I'll make a small batch and give it a go. See if it can harden/strengthen a piece of balsa. Yeah, I know, CA can do that, but it too is pretty expensive if you need much.

With acetone at $10/litre, it's not exactly cheap either!

Originally Posted by Master Splinter

With acetone at $10/litre, it's not exactly cheap either!

No, but it keeps a lot longer than a small bottle of (pre-catylysed) cactus juice. Might not need a $200 vacuum setup, either.

I finally found a reference to using acrylic sheet and acetone in an old thread here on the forums, in 'Pen Turning'. Thanks for the clue, Master Splinter.
https://www.woodworkforums.com/showth...276#post538276

Unfortunately, the link to more info in that thread is dead.

Apparently it does work well, but like Cactus Juice, needs a vacuum to pull it into the timber for best results.

On the up side, it shouldn't go off like Cactus Juice, if it sits on the shelf too long.

I've been doing it to saw handles.
https://www.woodworkforums.com/f278/vaccum-infusion-friable-wood-180942

Originally Posted by rob streeper

I've been doing it to saw handles.
https://www.woodworkforums.com/f278/vaccum-infusion-friable-wood-180942

Thanks Rob. I just read through your thread. Interesting.

So, MinWax Wood Hardener is dissolved polycarbonate? (I read your thread very quickly.)
Edit: It's stronger than acrylic, from memory, but acrylic sounds like it'd do fine unless higher strength is required. (I have no polycarbonate scraps.)

It's been so long since I last used the MinWax stuff that I'd forgotten it smells like acetone.

I have a small vacuum pump here that happily pulls 29inHg, but no container, apart from a 50 litre beer keg that I converted to a fermenter years ago. I'll see what I can come up with, and have a play when I get a chance.

Looks like I probably won't be buying wood hardener again, at least.

Originally Posted by Hermit

So, MinWax Wood Hardener is dissolved polycarbonate? (I read very quickly.)

It's been so long since I last used the MinWax stuff that I'd forgotten it smells like acetone.

I have a small vacuum pump here that happily pulls 29inHg, but no container, apart from a 50 litre beer keg that I converted to a fermenter years ago. I'll see what I can come up with, and have a play when I get a chance.

Looks like I probably won't be buying wood hardener again, at least.

As best I can tell Minwax wood hardener is simply polycarbonate in acetone, I'm pretty sure of the proportions I describe in the other thread.

I've found that the Minwax product is a little too concentrated for vacuum infusion, it has a low viscosity but I get better uptake when it is cut. The cut ratio varies with the type of wood being infused.

As to the price of acetone, you guys in Australia seem to pay a lot for everything. Here a gallon of technical grade acetone at the home store is still reasonable at $15-$20. However, loss is not high unless you spill the solution and it can be re-used without problem. Just be careful with lighter types of wood as the solution will pick up color from use on dark woods.

Be careful with selection of a vacuum chamber, don't want to send anyone to the hospital. Be sure to check the chemical compatibility of your chamber too. I see a lot of people selling infusion chambers on eBay that appear to be made using stainless steel cooking pots. Nice because they won't shatter and are likely adequately strong to handle -15 p.s.i./-760 mm Hg. The missus may object though.

Originally Posted by rob streeper

As best I can tell Minwax wood hardener is simply polycarbonate in acetone, I'm pretty sure of the proportions I describe in the other thread.

I've found that the Minwax product is a little too concentrated for vacuum infusion, it has a low viscosity but I get better uptake when it is cut. The cut ratio varies with the type of wood being infused.

As to the price of acetone, you guys in Australia seem to pay a lot for everything. Here a gallon of technical grade acetone at the home store is still reasonable at $15-$20. However, loss is not high unless you spill the solution and it can be re-used without problem. Just be careful with lighter types of wood as the solution will pick up color from use on dark woods.

Be careful with selection of a vacuum chamber, don't want to send anyone to the hospital. Be sure to check the chemical compatibility of your chamber too. I see a lot of people selling infusion chambers on eBay that appear to be made using stainless steel cooking pots. Nice because they won't shatter and are likely adequately strong to handle -15 p.s.i./-760 mm Hg. The missus may object though.

Rob, acetone here isn't as expensive as Master Splinter said unless you buy it in a 750ml plastic bottle, (~$7.50). I don't know the exact price, but it would be very cheap by the gallon, or even a 20 litre drum.

I forgot to mention, my 50 litre beer keg/fermenter is stainless steel, and fairly heavy gauge. I'm just not sure if it would survive full vacuum from my pump due to it's large surface area. At around 18-20inHg though, it would be fine, and has a really good seal ring under the lid, (the lid's the stainless steel bottom of another similar keg, with a small valve in the centre). I have vacuum fittings that would almost go straight in if I decide to use it. Bloody big, though, for a tiny piece of wood.

This is the 50 litre fermenter (come vacuum chamber?).
The seal just sits there and is sandwiched by the lid, usually held down by the threaded rod in the pic. With vacuum applied, the rod wouldn't be needed, but I might need to glue the seal in place.

Fermenter with lid and lock bar in place.jpgFermenter open.jpg

I wonder how many pen blanks it would hold?

I think I'll put the Corningware back and use this. Should be more than strong enough, has a small volume appropriate for saw handles and it's cheap at $0.99 each.

mixing bowl.jpg