Finishing MDF or Trupan to a smooth surface

[Brady Watson]

Ok Guys...I need some help from some of you finishers out there. I am working on a large 3D relief project using Trupan (and have tried MDF as well).

The problem I am having is that I cannot find a product to seal & raise the hairs that is easy to sand AND leave a smoooooth surface. I have tried watered-down Titebond I, Epoxy, wood hardener, Deft SS, Kilz, FSC88, Zinser B-I-N and a host of other products in hopes of knocking off the hairs and getting a consistent surface. Epoxy and FSC88 worked pretty well, but after sanding, there are dips/voids/pocks in the surface...I need to spray a smooth enamel finish on this and I am getting to the end of my rope!

Thanks!
-Brady

[bleeth]

Duratec from Dupont-First coat looks like heck-Sand it and apply the second coat and it sands like glass. (Used by FRP plug builders everywhere).

Dave

PS: The cutting is the easy part-Finishing is h----------

[Brady Watson]

Dave,
I have Duratec here...(made by HawkEye)...I use it for FRP stuff. Didn't think to use it here...

Would you sand the Trupan 1st?...or just spray, sand, spray? I wish it wasn't 'nasty-polyester' scented...

-Brady

[paco]

I would spray first prior to any sanding, so after that, I would hope that it would hold the hair while a soft sanding... maybe a second step to remove more if need. I'd look for something that would soak in some of the surface of the material.

[mikejohn]

The Duratec range of products(marketed by HawkEye in the States), could have another name in Europe, as I haven't found it by Googling. In fact I have found another product with this name. Anyone know what name these products are marketed in Europe, and by whom?

...........Mike

[joe]

Here's my favorite.

Bulls Eye shellac. It's a good base for allmost everything and sands smooth.

For a really slick surface over shellac, High build primer.

j

[bleeth]

If your relief is done with a small step asnd has mimimum ridges you can probably go straight to priming.

Dave

[patricktoomey]

I agree with Joe, Shellac is what I almost always use on MDF or Trupan. First I rub the whole thing with an abrasive 3M pad to get the worst of the dust and hair off and then I start with a thin cut of shellac, like 1 lb (1 pound of shellac flakes to 1 gallon of alchohol). That soaks in enough to raise the remaining hair which you can easily sand off. One more coat if you need it and then build to your smooth topcoat with a high build primer.

[stickman]

What are you using for a high build primer?

Could Shellac be sprayed with an HVLP?

Jay

[gcoding]

I had a job out of mdf that I was going to paint a dark color. Instead of sanding the hair like stuff from the mdf. I justed used a plumbing soldering tourch long enough to burn the fibers not the relief..