I was just putting together an article for NSRA's Street Scene magazine, and I thought this part of it would be a great tutorial for this site. This should be a very easy project for anyone interested in working with fiberglass (even though fiberglass cloth is not used!)
1) Here's the reason for this little project. The AC unit is too close to the back side of the dash. As you can see the gauges do not even come close to fitting. A simple gauge pod will be built and upholstered to push the gauges outward, and allow clearance between the AC unit.
2) On a piece of 1/8" LuAnn plywood, the base pattern of the gauge pod is traced out. The dashes face is curved so 1/8" LuAnn is used because it is flexible. All six gauges are layed out, and the outline is traced for the pod. Get creative here if you like, i chose to keep it simple with an elliptical shape.
3) The pattern from step 2 is cut out with a jig saw, and any rough edges are sanded down. The LuAnn is then clamped to the dash and holes are drilled into the LuAnn, through the dash. This will allow you to screw your base LuAnn piece to the dash. Be sure and mark top and bottom of your LuAnn piece in reference to the dash.
4) Just like we layed out the pattern for the base LuAnn piece, a top piece is layed out on a piece of 5/8" MDF. I made my top MDF piece smaller than the Luann, so it will give the gauge pod a nice tapered effect. Router or sand the top edges to a nice curve. Drill pilot holes for the center point of the gauges, but DO NOT drill/cut out the entire diameter of the gauges, just drill a small (under 1/4") pilot hole.
5) Attach the LuAnn and MDF together with small spacers made out of scrap. The gauges protruded about 1.5" from the dash, so i went ahead and made the thickness of the entire gauge pod 2" to give us a little extra room. Cut the spacers accordingly and attach them in between the LuAnn and MDF. Two worked just fine for my pod.
6) Heavy fleece is stretched over the gauge pod "mold" you have made. It is stretched fairly tight, but still allowing the LuAnn to flex. The fleece is stapled on the back side of the LuAnn.
7) Tape off the area of the dash that the pod sits in. I used PAM high yield food release as a mold release. Spray it where the pod sits, and all around the surrounding area. I made this pod on a painted dashboard, so i had to be super cautious or i could have ruined the paint. Tape off every portion of the dash you will be working on to avoid dripping resin on it.
8) Screw the pod (with fleece) onto the dash using the holes you previously drilled. Be sure the base of the pod is nice and flush with the dash. Mix your resin, and apply it to the pod. Make sure the fleece gets "soaked" with resin. Let it cure on the dash, do not remove until it is cured.
9) Once the resin has cured, unscrew the pod from the backside of the dash. If you used a good coating of PAM (or other mold release) your pod should practically fall off. Congratulations, you are about done.
10) With a good quality hole saw or hole cutting tool, cut out or drill out the gauge holes to their exact size. Remember the pilot holes you drilled in step 4? This is where they come in handy.
11) One layer of heavy fleece is plenty thick for a gauge pod. This "plug" from one of the drilled out gauge holes is just showing how thick a properly soaked piece of fleece will get. The fleece starts at the black marker line. You can see its about 3/16" thick.
12) The fun part. Sand this thing until its smooth. I started with a 3" sanding disc on a air sander, then finished it by hand. I gradually worked down to 60 grit sand paper. If you are upholstering your gauge pod like i did, 60 grit is plenty fine.
13) Test fit your gauge pod to your dash. Check for uneven gaps where it meets the dash. If its not perfect, dont throw it in the trash, a little filler wont hurt a thing. Use duraglass or a filler similar and build up the gaps or low spots. Sand again until its smooth. Test fit and repeat until you have a nice smooth, and perfectly fitting gauge pod. Luckily i avoided any more sanding.
14) Upholster the pod, attach it to dash (once again using the holes drilled in step 3), insert the gauges, and you are done. Put that dash back in the car and admire your handiwork!