47-15: Snorkle to SDS Throttle Body Interface

In a previous post, i talked about the choice of snorkle. I also sought some advice on the Van's forums and got a bunch of responses - to be fair, most of which were (TLDR) - "fibreflass is easy, just fibreglass a new transition". 

I decided that since i am losing a bit of weight FWF, with the loss of the fuel pumps and mags (and repalcement with much lighter SDS parts), the added weight of the aluminium flange on the snorkle was probably going to be ok! Also, to do any fibreglass modification of the snorkle would need to wait until the engine was built, and the baffles were on. I wanted to get this done now, so there is little baffle work needed between the engine being built, and being able to run it. 

So, to start, i needed to roughly trim the snorkle mounting flange, then match drill some reference holes between the snorkle and the flange - mostly to hold the thing on when fibreglassing. I then used some epoxy and flox to initially glue the flange on (and created a small fillet on the inside with the extra flox). 

Lots of holes were drilled - 4 for reference and clecoing on - the rest to allow glue to squeeze through.

What could go wrong? This part is only worth $850!

The edges were rounded over to allow the glass to lay down better in the next step.

 I made the flox into the consistency of peanut butter (without the chunks)

Here you can see how the flox squeezes through the holes in the flange, adding mechanical strength to the joint.

A little fillet around the edge smooths the transition to the glass.

A small fillet on the inside will help me make a nice smooth transition using epoxy and micro, while adding strength to the corner. 

Once this had cured, i wanted to add a couple of layers of 9oz glass around the flange. I had initially cut it into little squares, which were parrallel with the weave, but this was a disaster. These would not lay down flat due to the compound curves, and i ended up wiping it all off and coming back the next day to try again.

The little squares were cut parallel to the weave - this didn't work.

The next day i came back and cut some longer strips on the bias (at a 45 degree angle across the cloth). This worked a lot better and was able to bend around the compound curves. I used 4 layers of 9oz cloth.

These went down beautifully compared to the little squares

Once that was cured, i cleaned it off with iso, then sanded with 80 grit until there was no shine, then cleaned again. I mixed up some epoxy and micro and pasted this on to fill all the holes in the cloth. I added a fillet to the inside of the snorkle, to smooth the transition to the new flange. Will refine this later with sanding and a second coat of micro. 

Forbidden icing.

The initial fillet.

The fillet had different widths depending on how the snorkle curved on the inside.

Most of this micro was sanded off, and i used a second coat of micro to further refine the shape. The second coat is a little bit yellower, as i used some fast hardener which was a little older. 

A second coat of micro to refine the shape

Once this was cured, it was sanded once again.

Most of the micro gets sanded off - but fills all the low spots / pin holes etc.

Nice and smooth transition.

Fibreglass is the best - not!

Finally, a flow coat of neat epoxy was added to fill any holes in the micro, and to give a final sealing coat to the inside and outside.

This will be the final finish inside the snorkle - the outside will be painted once it is joined to the filter frame.

That ends the work on the snorkle and baffles for now - will need to get the engine built and the baffles installed to match drill the snorkle to the filter frame.