Making Templates Question

[Jim Roche]

I'm wanting to make some templates to use with a flush trim router bit and was wondering if anyone of the forum has used any of that PVC sheet goods that they sell at the big box store? I planned on using the templates at least 4-6 times and maybe more down the road. I know there have been a lot of conversations about template making using phenolic plywood, MDF and plexiglass but just want to see if any has used any PVC? The cost seems to be pretty reasonable at $70 a sheet. Any drawbacks that you can think of?

I appreciate your input.

Jim

 

[Mike Davis]

Haven't seen that product, but I would be concerned with heat from the cutting blade transferring through the bearing to the plastic causing shrinkage or actual melting of the PVC plastic. I would want to test a small piece before I invested my time to make patterns that may not last through a couple uses. I believe PVC has a fairly low melting point.

edit for google result:

PVC starts to decompose when the temperature reaches 140 °C (284 °F), with melting temperature starting around 160 °C (320 °F).

 

[CDPeters]

I've had the very problem Mike describes with plexi/lexan. I typically use 1/4" hardboard for templates, it's much cheaper. MDF will work for a couple uses, but I find the edges tend to get fuzzy.

 

[Jeff]

I use MDF because it's easy to cut and sand to shape in order to get a nice smooth template. Then use a flush trim router bit with the bearing riding on the template.

I don't understand how Chris's templates get "fuzzy" with the bearing riding on the template surface. :icon_scra

 

[Charlie]

Jeff,
Hardboard is harder than MDF.

Hardboard is a high-density board made from compressed wood fibre, bonded together essentially with heat and pressure only. It is usually 3mm or 6mm thick only and smooth on one side or both sides. MDF is a medium-density board made from compressed wood fibre, bonded together with a resin and smooth on both sides.

 

[sawman101]

I prefer 1/4" hardboard and a !/2" pattern bit. The bearing is just below the routers collet, and rides on the edge of the template or pattern.

 

[Melinapex]

I just made a template for the same reason and made it out of mdf, then attached a peice of 1/4 hardboard and mirrored the shape with a flush trim bit. Since I was using double sided tape I was worried about the mdf tearing away with use. Now with the hardboard I can just replace it and keep the mdf from wearing out. I had the material so no cost to me......

 

[patlaw]

Here's the hardboard I normally buy. Where do you get 1/4" hardboard?

Lowe's Hardboard

 

[Jim Roche]

Capital City sells both 1/4" and 1/8", I typically buy tempered hardboard.

Jim

 

[KenOfCary]

I also prefer hardboard for templates although I'll occasionally use MDF. I have some Router Bowl templates that are made out of some kind of plastic that worked fine though. These I purchased from Rockler or MLCS - don't remember which.

 

[CDPeters]

I don't understand how Chris's templates get "fuzzy" with the bearing riding on the template surface. :icon_scra

Probably humidity. I've seen some folks treat the edge with glue to harden it, then sand smooth. Hardboard is just much easier & quicker.

 

[Endless Pursuit]

If the templates will be used repeatedly, I seal the edges of both hardboard and MDF with a clear epoxy I sell. You would get the same results with a coat of CA Glue or a clear polyurethane - penetration then harden. Both hardboard and MDF will get fuzzy and lose shape after several uses, especially if the piece being finished is thick compared to the pattern requiring extra force to get a clean edge.