I have had interest in a duck tail style spoiler for a long time but the cost of $300 plus shipping is too much for me, especially when I have read that several members have had "issues" with them. So I thought I would try to make a duck tail style spoiler. There are a few threads about spoiler making but many of them no longer have pictures (https://www.thirdgen.org/forums/auto...m-spoiler.html) or really go into detail so if I'm making a mistake help me out. The wood blocks that you see will be totally wrapped in fiberglass and their purpose is just to give me a skeleton for the fiberglass until it is strong enough by itself.










Since I wanted the front side of the spoiler to be flat it meant that it had to be taller in the middle and shorter on the sides because the trunk lid is curved backwards. I'm not sure if the size is too much, I do not want this looking like fast and furious. So speak up and let me know if there is a consensus that this is OK to continue or belongs more on a Honda....

 

Interesting and unique look...but my personal opinion is that it is too tall, especially in the center. I don't think it'd look very good when finished.

 

I'm kinda the same thought. But if it is all the same height I would need to make it thinner in the center of the spoiler and wider at the sides.

 

I like it. little tall but. Snap a line from corner to corner, rip that off, blend it a bit and wall ah. Is there a belly/bevel to it. (side pic) I like it. Nothing on the rear quarters coming up to meet? IDK... I like it. I think you are on the right track.

-Dan

 

I'm only working on the trunk section right now but it will have the side pieces like the stock 3 piece. What do you mean smap a line from corner to corner?

 

In the 3rd pic, from the right corner to the left on the back of the spoiler. make that flat and not curved. I see that your wood frame may make that a little difficult being its higher in the middle. snap a line, is a term that construction workers use, meaning hook a snap line (string with caulk) and snap a straight line and rip it off with a circle saw or what ever your liking.

Anyways, I think your on to something. Keep playing with it. what do you think the sides will look like?

-Dan

 

If it were me I might do some things differently, not that yours is bad, I just have a different thought process. My thoughts on the wood blocks is that it may eventually show through, especially if attached to the fiberglass. The sun will play a major factor in this especially if it's painted a dark color.

Wood expands and contracts differently than fiberglass and it may cause areas of stress/tension that may show through. To help with this I would not glue the center pieces and allow them to float (either to the fiberglass face or the dowels). One alternative if the spoiler is actually flat, is to buy some flat stock of fiberglass/composite (usually expensive). Could maybe even run 1/8” plywood instead and glass over the top of that.

Styrofoam is what I would try, but you may still need wood blocks along the bottom for stronger attachment points. Styrofoam is a lot easier to shape and make changes and/or scrap and start over again. Could even tape the foam down including the sides and then cut slots that match up with the opening between the deck lid and body. Making specially shaped sanding blocks may help as well, or hot-knifing while being careful of the fumes. The drawback with foam and the actual fiberglass is that dust from either can be very bad to breath in. Also with foam you are often stuck using epoxy resin which can be expensive Google “composite Styrofoam fiberglass” if you're not familiar with how composites get their strength and/or hard points. Many books on the subject as well.

I had thought about doing something similar and noticed the angle of the tail lights vs. the spoiler etc., and that might help you determine angle for the spoiler if you were to start over again. These cars have a lot of subtle curves that you wouldn't notice until you get into it.

Sorry to point those things out as you're pretty far along now. Just throwing ideas out there in case it helps. What you have built looks well crafted and thought out.

 

The back needs to be curved because the trunk lid is curved back. Only way to correct it is not to make the back of the spoiler in the middle not follow the same contour as the sides.

 

I originally went the foam route but I couldn't get the thing flat in the front.

 

Oh, because of the compound curves? Yes I guess that could be difficult.
I can think of 2-3 ways offhand but it would probably be more intensive than what you're doing now.

 

I'll grab a saw and see about cutting the middle wood piece down and seeing how it looks. That should cut the height by an inch.

 

Took some of your advice and cut a bit off the top, it is now shorter and fairly flat at 7" tall. I had to remake the back contour pieces. Now how does it look?




I think that the Hawks spoiler is 5" or 6" tall, can't recall.

 

I commend you on your efforts. I think that looks better than the rounded whale tail you initially envisioned. This car has so many Edges that rounded parts generally don't flow with the rest of the vehicle. Is it straight ? I cannot tell from this pic if its straight or not. Maybe I didn't see it in the post, but are you going to make the matching pieces that attach to the body on the rear Panel left/right (like hawks) ?

 

Actually.. if that skeleton was made in a similar fashion out of a polished metal, and left exposed with the whale tail on top... that might look pretty sweet.... just a thought

 

This project has taken a back seat to all the engine bay work lately. The spoiler is straight on the top and not curved. I will make the side pieces. I have considered making it out of steel. Always an option. Really wanting a duck bill I stead of the 91-92 wing. Those wings are decorational and these are at least arguably effective.

 

Actually, the better way to do this is, use drill rod to make a wire frame. Drill rod is easily formed to make the contour of your choice and is able to be welded. Then use flat bar stock to create the mounts and place a through bolt welded in place to mount to hatch. Wrap with fleece and coat with resin. A couple of coats of fleece/resin will give plenty of material to make fine adjustments, then do usual body prep and paint.

 

I found with the long pieces that when the fleece is stretched and taught it will still sag once resin is applied unless you use lots of supports or start with thin coats on the front and then once hardened soak the back. For flat pieces I prefer the way I did it by making the flat section on the floor or table so one side is perfectly flat and smooth with no sanding required.

 

If I made a metal frame I would just do the whole thing in metal. Use 22 gauge for the top and back.

 

You have a lot of supports now. Replacing what you have with drill rod, will not only make it stronger, and lighter, but also not have any expansion from moisture wicking in. If the wire frame is constructed properly, it won't sag when the fleece is applied.
If you're concerned about it sagging, place a layer of chicken wire over the wire frame. It is easily contoured also, and can add support between the frame.

 

Hadn't considered chicken wire. The wood will be encapsulated in fiberglass so I don't think expansion would be much of an issue.

 

Nothing really new here. Just wanted to add that the materials and your time (depending how much of it you have) quickly add up. At this point I have a little less than $100 in materials and lots of time.

I may try buying a stock 3 piece spoiler from a junk yard and elongating it with some similar material. I'm not sure if it's a urethane, abs or regular plastic.

 

I believe I have some of those pictures saved from Johnny iroc. I'll look tomorrow. As far as building it, it would probably be easiest to shape out of foam and wrap it in fiberglass.

 

I tried that unsuccessfully. I couldn't get the surface flat enough. I would have needed a table saw at least.

 

I know I have more. But these are what I could find today.

 

That looks great, I would be interested in knowing how you did it. I haven't worked on the spoiler for a while. I want to get the body and panel in paint before the heat of desert summer arrives so I put all other projects on hold. Again though, I couldn't get the leading surface flat when I used foam and tried to shape it. Only thing I could think of was a table saw...

 

Tibo,

JohnyIROC (TGO MOD - Ontario section) has a similiar 5" duck spoiler on his dark red IROC.

Perhaps you could PM him to see how he made his

Profile link

\https://www.thirdgen.org/forums/member.php?u=3911

 

I had seen his spoiler before but hadn't contacted him. There is also another member that used a second gen spoiler and just cut and glued the center/trunk/hatch section for the appropriate width that also looked good. I might try buying a stock junkyard spoiler and lengthening it also.

 

That is johny Irocs picture, my phone wouldnt allow me to post several pictures at once for some reason. i saved them from his build thread. i dont believe he is an active user anymore.

 

That's pretty cool!

 

Could try making it in wood then taking a mold from it in glass, and using that to make a glass spoiler. Shapers that build surfboards use the foam and epoxy resin process, probably lots of board making vids on youtube if you want to go that route. Aircraft back before 1935 mostly used fabric over wood frame construction, light and strong, the fabric was doped, which meant coated with a early form of epoxy resin to make it air tight and stiff.

I did work for Glastron boats for a while and I can tell you that in fiberglass boat construction plywood and wood blocks are commonly used to reinforce glass hulls without any problems.

 

If you aren't using a mold , you will never get it flat and smooth by building up alone. You have to build up beyond what you want , then sand down to flat and smooth.
If you make a mold, you build the blank with foam , wood, whatever, it doesn't matter, then sand and fill smooth, then cast a mold from that. Then you cast the part from the mold and the outside is the shape you want.

 

Could look into rigid shaped hotwiring the foam along the length. Might be able to get the compound curves that way. Be careful of the type of foam used and toxic fumes.

 

I like that it's tall in the center. Looks very Nascar-ish, which I love