Dan_Tech@Charter.net
11-12-2003, 02:18 AM
We experimented with building the graining into the routing process.
For realistic graining - you need to V groove the lines. It ended up taking 10x longer to cut the grain pattern. I figured I could just use a .5 engraving tip but without the realistic up/down V groove it never looked right.
Heres the process we use now. Cleanest results for the fastest turnaround.
1. presand the HDU - gets all the manufacturer grime off - opens up the pores.
2. prep - we use Jay Cookes, use a combination of a roller and a wide squeege - really gives a glass smooth finish - no pinhole air pockets.
3. Apply sandblast resist to the whole sign over the dried prep.
4. Put the sign on the router and route out the letters and designs into the resist. This saves you the plotter step and the resist doesnt get stretched out. We leave a .25" offset border around the letters - this gives the letters a natural flat border instead of grain up to the edge which makes it hard to read letters sometimes - but you can do it whichever way you want.
5. We send the blank off to blast using a Grain frame - thats the comb tool Tom mentioned. If you have deep pockets buy it - otherwise look at the pic of one and you can make your own using plastic wire lines for less.
6. While the blanks off getting blasted we cut the letters from .25 up to .75 HDU or PVC. I prefer PVC - sharper edges, finishes faster.
7. Get the blank back from the blaster and stab brush 2 coats of paint on it
8. Glue the letters on. You can pocket them for extra grab - or offset them using spacers for more effect.
Your fails here are leaving sharp edges on your letters. The router bits leave incredibly sharp edges. This prevents water from falling over the edge due to capillary reaction. You "ease" the edge by hand smoothing (least favorite method) or using a half round or Chisel bit to put a rounded or angled edge on the letter. This allows the rain water and all its contaminents to sheet down the letter. Otherwise you end up with these little water drops which act as magnifying glasses for the sun and burn in pits into the paint just like it does on your car hood.
For realistic graining - you need to V groove the lines. It ended up taking 10x longer to cut the grain pattern. I figured I could just use a .5 engraving tip but without the realistic up/down V groove it never looked right.
Heres the process we use now. Cleanest results for the fastest turnaround.
1. presand the HDU - gets all the manufacturer grime off - opens up the pores.
2. prep - we use Jay Cookes, use a combination of a roller and a wide squeege - really gives a glass smooth finish - no pinhole air pockets.
3. Apply sandblast resist to the whole sign over the dried prep.
4. Put the sign on the router and route out the letters and designs into the resist. This saves you the plotter step and the resist doesnt get stretched out. We leave a .25" offset border around the letters - this gives the letters a natural flat border instead of grain up to the edge which makes it hard to read letters sometimes - but you can do it whichever way you want.
5. We send the blank off to blast using a Grain frame - thats the comb tool Tom mentioned. If you have deep pockets buy it - otherwise look at the pic of one and you can make your own using plastic wire lines for less.
6. While the blanks off getting blasted we cut the letters from .25 up to .75 HDU or PVC. I prefer PVC - sharper edges, finishes faster.
7. Get the blank back from the blaster and stab brush 2 coats of paint on it
8. Glue the letters on. You can pocket them for extra grab - or offset them using spacers for more effect.
Your fails here are leaving sharp edges on your letters. The router bits leave incredibly sharp edges. This prevents water from falling over the edge due to capillary reaction. You "ease" the edge by hand smoothing (least favorite method) or using a half round or Chisel bit to put a rounded or angled edge on the letter. This allows the rain water and all its contaminents to sheet down the letter. Otherwise you end up with these little water drops which act as magnifying glasses for the sun and burn in pits into the paint just like it does on your car hood.