Finishing Trupan & Extera

[joe]

Many sign artists continually dream of the perfect carving medium. Those of us who came up with a chisel & gouge could argue for hours as to which is better, Buttercut or Basswood. I still marvel over all the historical Oak carved furniture, but none of these last very well outside. Today we have synthetics that address exterior weathering and are router friendly.

When I started with Trupan I couldn't believe how nice it carved, light weight, sanded and hand carved well, cheap, lightweight, did I mention cheap, and just an allroud good sign product, but not an exterior product. We also use quiet a bit of HDU but it is expensive, and time consuming to finish.

Next we tried Extera but is was too heavy, and crude. Good for special products but heavy.

Back to Trupan: The weather proofing technique that seems to work best is as follows.

Two quick coats of shellac, burshed on. Not spray or rolled. Two coats of Expoxy or Fiberglass Resin.

While this leaves a beautiful dense product there is still the problem of through holes when attaching the sign to posts or building. I am sure some of you guys have a good solution for this. We are now drilling a 1/2" hole, tape off one side, and fill with epoxy, and tap a holw for bolt.

Would sure like to hear any test you guys have done.

Mark Fair is close to finishing my Web site. As a two person operation, I have strung this our for some time. Should be approx 75 more signs posted this coming week.

www.normansignco.com

j

[Brady Watson]

Joe,
If I had to mount the panels on a facade, I would machine a pocket to conceal the bolt heads and then epoxy in a plug made to fit the hole...although your method may be the same amount of work.

I have been messing with trupan myself this week. I have a small run of relief carvings that I need to produce and thought trupan was an ideal candidate for the project...especially since it is much cheaper than wide-width mahogany and the fact that the woodgrain won't be seen anyway.

My main problem is dealing with the hairs after carving. I don't want to lose/wash out too much detail on the relief...but need a smooth surface finish. Do you think that the formula you supplied above will work?

-Brady

[jay]

Joe, just took a look at your new web site and the beautiful product you produce. Fantastic work, well done.

The signs that look like they have been sand blasted were they cut with a router or where they actually sand blasted?

[joe]

Brady & Jay

Thanks for your interest in my work.

Perhaps the relief carving should be sprayed. It is very hard to determine the amount of shellac deposited this way, but may be the best in this case.

I have attempted some small relief carving on Trupan but had trouble with the interior of letters smaller than 3/8". Second try was to paint a thin coat of shellac on the surface and route. Nope didn't solve the problem.

Are you doing 3D work, what bit, how deep, etc.

I must tell you: I disvocered a great product for letters, & detail work, it's untempered masonite. The stuff is just great to seal, sand, and finish. Did I mention Cheap? "Looks good and lasts a long time".

Thank you Jay for the complements. As I mentioned there should be a gob more photo's of my work next week. Mark Fair is preparing them for publication.

I haven't met Mark personally, he lives down south and I am in Oklahoma, but decided to hire him once I saw his web work.

Jay I do one of a deminsional sign from wood, HDU, and wood products. I doubt that you can tell the materials on the screen but would be pleased to tell you about any that you are interested.

If I could figure out how to post photo's on this forum it would be good.

About half of my time is taken up with design, bookwork, repairs, ordering materials and pesky phone calls. Few cold calls mature into a sale. The sweet, purple headed, little old lady, realtor has never purchased one of my signs. I'm hopefull.

I work fast and do most of it myself. This is not by choice, but I am too picky and kink of hard to please.

Thanks again
Happy Routing

j

[jay]

"The sweet, purple headed, little old lady, realtor has never purchased one of my signs. I'm hopefull."
That is why I stay away from retail!

I cut for a couple of the sign companies here . . . I do not compete with them, I want to cut for them. I hope that this way I will get to cut for all the sign shops here and no one will see the need to purchase a competing CNC router.

I should mention I will also cut for some of the designers as well but only after the designers come to me saying the sign people they talked to can't do what they want. The sign companies now know that if I quote a job for them I will not quote on the same style or design for the store designers. Shoot, I make more money cutting for the designers because I try to charge what the sign company would charge them.

[Brady Watson]

Joe,
I am using an 1/8" ballnose to cut to a max relief depth of 1/4"...however I need 1/2" of meat behind the carving for the overall structure I am making, so I either need 4/4 lumber or 3/4" sheet goods. I am at the borderline with Trupan at 18mm/.70". For the most part, I am able to sand some of the hairs off with a Scotchpad...but usung straight epoxy tends to raise the hairs and may fill too much of the relief.

I'll post if I find the miracle product/formula for this sort of thing.

-Brady

[billmaj]

Brady, Joe
I have experimented with many products to discourage hairs on MDF in general, and trupan. Franklin International, the glue company, makes a product called "Woodsise Concentrate" that very effectively seals these most porous materials. In fact, it is made for this exact purpose. It is a concentrate that you can mix to the consistency that you like, either for spraying or applying by hand. The advantage is that it readily accepts many finishes as a top coat. The disadvantage is that after application the item still needs to be sanded prior to the topcoat. It does sand well but depending on the amount of detail you are contending with, this could be tedious as I am sure you already know. Franklin is located in Ohio, phone # 614-443-0241. They shipped me a gallon for free so I could try it and were very helpful in helping me arrive at this product based on the my description of my needs.

The next best thing that I use is a vinyl sealer made by Sherwin Williams. This product does not seal quite as well as the Woodsise but does not raise the hairs as much (solvent based vs. latex, dries very fast and sands very well). I generally apply two heavy coats before sanding. You should probably have spray equipment to use this though. I like it better than shellac because it has a higher solids content.

Hopefully this helps,

Bill

[Brady Watson]

Thanks for the tips, Bill. I am probably going to be using Mahogany or Poplar for the carved pieces and Trupan for the flat areas. I need to make 7 CD racks for a local radio station. Since they are going to be finished in a black dye, species isn't too important. Trupan would be ideal if it didn't take so long to get those hairs knocked down...especially since it would widen my profit margin.

I just casted a chunk of USG's Rayite 100. I have to wait about an hour before I demold it. It is a gypsum based machinable media that can be used for temporary tooling. I believe Boeing uses it for short run parts. I'll post when I get something machined with it. Apparently it produces low/no dust, puts off a chip, and requires no coolant/lubricant. It can also be used with HSS bits.

We'll see how it goes...

-Brady

[joe]

Bill,

Thanks for the information about the Woodsise Concentrate. I'm sure it works very well. Is this a water based formula? Will give them a call Monday

The true test for us is the roof test. We coat out lots of wood products, date it, and throw it on our roof top. We check in on them ever so often to see how they are doing. There it get all the test necessary for our approval.

There are three reasons I use shellac. It is very fast drying, goes deep, and is a good base for Epoxy which does the real sealing.
It's not very expensive and available. This isn't any thing I think you guys are interested in, as our signs are exterior.

Do you guys have the chatter marks I do. Fuzz is second to the tooling marks. Yes I've tightened, lubed, till I've given in, and resort to sandpaper. Hair comes off fast with a little abrasive.

You talk about fuzz, Extera is King of the crop.

Brady,

Try masonite and when finished, use a stiff kitchen bruch to smooth it off.

j

[Brady Watson]

Joe,
You can get 3/4" masonite untempered, right? I have only seen it in 1/8 and 1/4. That would be the ticket if it is available and I can get a nice smooth finish on it.

I haven't experienced chatter marks, but aside from a profile pass to cut it out, most of my moves have been 3D. One thought was to 'shell' the machined areas with a liquid 2-part plastic and then go back and machine it again to get a hair-free surface. That is just not very efficient at this point, but a viable idea if you wanted to hard-shell foam let's say.

There is a product called Permalac that is supposed to be good over 10yrs outside. You can get it through Sculpt Nuveau if you can't find it. Very nice stuff with UV inhibitors, although not water based. SN has a water base clear now. Not sure durability though.

Here's a few shots of what I am working on in Trupan. The file took me forever and a day to make and get right within the limits of Rhino and MillWizard. You can see it will be a very visible item, so the finish has to be higher than that of an exterior product. So far, mahogany yields the best carved finish, although I haven't tried doing one in Poplar. Entire unit gets a quick mist of brown dye followed up with a black dye so all of the material will be concealed.

This is a CD rack for a member-supported radio station. It holds 25 CDs and resembles the steps going to their old studio.



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Conceptual Rendering


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Trupan carved 1/4" deep


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Trupan Isometric View

-Brady