stevec1234 8th June 2010, 08:34 PM Hey guys,
Just a quick simply question really. I get a bit of bleed through when using techniglue with my bent veneer laminations. I have been sanding it back with 120g after taking the piece out of the form, It is a very slow process getting rid of the epoxy which has bled through. Would you suggest using a coarser paper say 100g or even 80g to cut back the cured epoxy and then it up with 120g.
I have been using an electric finishing sander to try speed up the process, would an orbital sanded be better suited to this job?
Cheers
Steve
Master Splinter 9th June 2010, 08:59 PM Bleed through as in the laminations are really, really thin and the epoxy is being forced through the pores and cracks in the timber, or just oozing out the sides of the laminate stack and dribbling everywhere?
If it's the first, make an MDF form to clamp against the laminate, and cover the form in duct tape or other PVC covering so that epoxy won't adhere. And maybe not so much clamping pressure...or use thicker laminations!
If it's squeeze out, there's no match for a belt sander with 80 grit.
stevec1234 9th June 2010, 09:03 PM Here is a pic, the squeeze out top and bottom is not a problem as it gets trimmed down its the bleed through which is a pain. I bought a decent flat orbital sander today which should make the job a little easier.
The pic is straight out of the press.
Master Splinter 9th June 2010, 09:40 PM Hummm....I'd be tempted to coat the whole thing in epoxy as a finish with that amount of bleed - you're not really going to be able to remove the epoxy-saturated area with sanding.
Other suggestions - use less epoxy (as thin a layer as you can get...the optimal thickness is like a few molecules), or maybe wipe on a sealing coat of epoxy, let it gell up for an hour or so (no longer fluid, but still flexible), then a coat of fresh epoxy and do the actual lamination. As long as the epoxy is still 'green' it'll bond chemically to new epoxy so you won't need to sand it, and it should hopefully be still flexible enough to conform to the shape.
AlexS 10th June 2010, 09:50 AM Splinter is on the money I reckon. Belt sanders are for removing lots of wood, not small amounts.
He's also quite right about the amount of epoxy needed. If both surfaces are covered, that's enough, provided the surfaces are clamped in contact.
stevec1234 10th June 2010, 12:54 PM I am not going to hit it with the belt sander. I bought the festool rts400, it is suppose to arrive today so we'll
see if that is any good on the areas with the light bleed through. I will also cut back on epoxy and maybe even ease off some of the pressure while clamping
AlexS 10th June 2010, 04:05 PM Yep, light pressure well distributed is better than too much at too few points.
stevec1234 10th June 2010, 04:42 PM Your right, with the rigs I have in place the pressure is even over the entire surface area of the form.
stevec1234 12th June 2010, 08:29 PM So, hitting the shell with the new orbital sander worked a treat, although I did not only focus on the areas which suffered bleed and I took off more material then I would of liked to, Oh well you learn from experience I suppose. I started with 100gritt, next time will use a low speed and only work the areas with the bleed and the from there work through the various papers. I will also be gluing some shells up next week so I will also cut back on glue on the in and out plys and see if I can ease up the amount of bleed.
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