abs sludge, denser/harder formula?

**scott_fx** · 02-13-2006, 12:19 AM

is there a way to make the abs sludge denser? It seem that the abs is just slighly softer when fully dried, and that is when you use a really thing mixture, if you use a thicker combo (less acetone) it seems like it traps a lot of air bubbles. The reason why i ask is that I'm casting some parts off a mold and i'd like to have the cast part just as solid as the rest of my dash. any ideas or suggestions? would heat help? vacuum?

**SMOKINV8** · 02-13-2006, 03:27 PM

If you're having problems with it, you might look into taking sheets of ABS and heat forming them to the mold. If the heat doesn't work well enough, you could do some expirementing with spraying a little acetone/MEK on it to soften it, but obviously don't soak it. This would help prevent the air bubble problem, which should relate directly to the density issue.

Something else I'm wondering about... what is the source of the ABS you're melting? The thicker area's I did didn't seem to flex any more than the rest of the panel, but then again, I didn't have any large flat area's either. It might end up just taking more thickness to get what you're looking for.

**scott_fx** · 02-13-2006, 04:40 PM

thanks for the reply, i'm not sure how to work with heat forming. would i need to make a vacuum chamber or is it just as simple as heating the abs up until it's 'gooey'. the mold is made out of a rtv type of product from smooth-on. it's very jelly like and i dont htink it'll stand up to any pressure without distorting.

thanks for the help so far

**MATRIXSHARK** · 02-14-2006, 04:05 AM

I have an idea worth trying, but I haven't tried it yet.

I've noticed that the solvent works great on ABS but has no effect on other plastics. I wonder, if we took one of these unaffected plastics and ground it into a very fine dust and then mixed that dust into the ABS sludge would it act like a thickener?

**scott_fx** · 02-14-2006, 12:27 PM

i think that would act the same way as airpockets, since it's not bonding it'll make it more brittle... i think

**SMOKINV8** · 02-14-2006, 12:35 PM

I don't think there's a good answer for the way you're wanting to do it. If you use heat, it causes the compound to swell up like a balloon, then deflate when the heat was removed (or the air bubble popped). I tried using heat on my first go with the ABS sludge when it wasn't drying fast enough, and that was my result. FWIW, I don't think it was any more solid than the rest of it.

**scott_fx** · 02-14-2006, 12:37 PM

thanks.
the best results i've gotten in my 3 attemps was the last one. ultra thinned 'sludge' applied in layers. it's reducing the amount of air pockets but not 100%. if i can't come up with another solution, this may work. keep the ideas coming though.

**SMOKINV8** · 02-15-2006, 06:43 AM

Just out of curiousity, how long are you letting your mixture sit before you apply it? And how often are you shaking/stirring/mixing it?

**scott_fx** · 02-15-2006, 12:42 PM

i think it was sitting in my room for a month or longer for the first application (which was the worst) the second try i mixed in some more acetone to thin it out immediately before i poured it and then the third time i did the same thing, with more acetone and the thinnest misture came out the best...still airpockets in there though. I added some more acetone and sludge to the mold last night and i'll check it tomorrow to see what the final result is (since it takes a long time to harden completely, it may have to wait till friday)