Need help with Epoxy Putty (Apoxie Clay brand)

[darcness]

Well, I'm a long time reader, newly registered user to the boards. I used to haunt over at some other site, which will remain nameless. I've grown tired of the children over there who constantly compare e-peen sizes and decided to join up over here at DIYMA. Seems people here are more mature and genuinely want to help others out.

Anyway, enough about me and my rant, on to the question!

I recently decided to have a go with some product we got in work as a demo. It's called Apoxie Clay and is basically just like any other epoxy putty out on the market. It's the first time I've done any real fabbing and things went very well. It was a breeze to work with this stuff and I'm on the home stretch now. I just need to do some more sanding work and then give it the final coat of flat black.

My question is this... I'm looking to get a nice clean and FLAT surface. Right now it's fairly flat, but still has some bumps here and there. I was thinking of using a block sander to get a perfectly flat surface, but have little experience sanding this stuff (or anything like it for that matter). I was just wondering if anyone has some tips on how to sand something to a perfectly flat surface.

Also, is 80-100 grit paper too rough to start with? I have 320 and 400 for finishing work. If I hit it with 100 or so grit first to flatten it out, then finish with 320 or 400 is this a good way to go about it?

Thanks in advance for any help and I'm happy to finally be posting rather than just lurking here at DIYMA. :D

[brendan 67]

Hi.Havnt got any experience with that product,but plenty with bodyfiller and fiberglass.If the ripples are not really ugly 100 grit with a block will be good.Then when its straight,finish it with 220,320,400.Keep the block going in different directions so you dont sand grooves or lines into it.Bigger blocks are better than smaller ones.You can get semi rigid type blocks like Durablock,in all different shapes to help with curves aswell.:)

[darcness]

Cool, sounds good. I can basically get a block big enough to do the entire piece at once, so that will avoid the grooves and lines. I figured a block would be my best bet, just wanted to get some opinions.

Thanks!

[tommyd]

I would stat with a low grit and switch directions every time you change grit. Work you way up make sure you have all the sanding marks from the last grit out before you start with the next grit. If its really bumpy, or hard to sand you might need to start out with a file.

Grand Blanc huh? My step mom works as a teachers there. Seems to be lots of people from Michigan on this board!

[bretti_kivi]

... or a rubber-backed 120 / 180 grit sanding roundel on a cordless drill. that way it won't be too fast, but will still be effective at removing the humps.
However, it might be too effective.

Ok, so, you take some contrasting paint. spray uniformly. Take your 320 grit wet'n'dry on a reasonably sized block and sand away. Where the paint is still afterwards, there's a hollow to fill in. "rinse and repeat". It's a PITA to get it completely flat. There's no such thing as too much water; some washing-up liquid (fairy? dishwash detergent?) helps to bind the dust. I use a sprayer and it's easy to clean the paper every few minutes as it blasts the caked paint away.

I would also test the effect of 100 or so before hand; don't use any coarser than you must because every application will remove material.

Personally I don't like to start lower than 120 / 180 / 240, depending, and then downgrade to 100 or 80 if I have to. Practice makes perfect. I'll also take it up to 400 and higher (selection of 400-600-800-1000-1200-10µ available) to get a really nice finish.

Bret

[jp88]

... l

Ok, so, you take some contrasting paint. spray uniformly. Take your 320 grit wet'n'dry on a reasonably sized block and sand away.away.
Bret
Or you could use a Carolina boat builders trick and mix a contrasting food coloring with denatured alcohol and paint it on. it dries pretty quickly and is pretty cheap as well

[bretti_kivi]

now that is an excellent idea, like that.