How to Build a Cus­tom Wind­shield Frame!

Hot Rod - - Contents - Jef­fer­son Bryant

hKus­toms are all about styling—tak­ing an orig­i­nal body, chop­ping it up, and re­design­ing it to fit the vi­sion in your head. That is one of the things that makes build­ing cars so much fun: you never know what you are go­ing to see next. When you have an art deco model, such as this 1941 Lin­coln Con­ti­nen­tal, much of the orig­i­nal styling is al­ready beau­ti­ful—just a few tweaks here and there to make it yours—but there’s one area that was a ma­jor fail­ure: the wind­shield frame. Un­like the rest of the body, which has bold curves and swoopy lines, the wind­shield frame is plain and bor­ing. In all hon­esty, it looks like it be­longs on a VW Thing or a Jeep, as op­posed to one of the most beau­ti­ful art deco pro­duc­tion cars.

The re­al­ity is that ev­ery­thing above the door line is wrong on this car: the wind­shield and con­vert­ible top. The top is be­ing changed out for a hand­built Car­son-style top, but what about that wind­shield frame? It’s far too flat and square to be left as is. We could try to mod­ify the cast-iron frame, but it would still be a lit­tle too up­right, and al­ter­ing the an­gle would mess with the side win­dows. What we want is a swoopy frame that evokes the styling of the 1930s coupes, oth­er­wise known as a Du­Vall-style wind­shield. We just have to build it.

There are a cou­ple of ways these things are done. We could spend months try­ing to ham­mer-form sheet­metal into the look we want, which an ex­pert me­tal crafts­man can han­dle, but we aren’t that skilled with a ham­mer and dolly. We could search for a car in the sal­vage yards to cut up and mod­ify into some­thing that re­sem­bled what we want, or we could start over from scratch and build a de­sign that matches our ideas and doesn’t break the bank; with that in mind, we are go­ing to cast our own wind­shield frame.

Tech­ni­cally, we aren’t cast­ing in-house—that will be han­dled by a lo­cal foundry that spe­cial­izes in small pro­duc­tion parts.

We are de­sign­ing and build­ing the pat­tern for the mold. The pat­tern is the form that is used to make the mold it­self. There are some crit­i­cal fea­tures you must pay at­ten­tion to when lay­ing out a part that is go­ing to be cast, namely drafts and un­der­cuts. Draft is the an­gle of all sides when the part is lay­ing in the cast­ing po­si­tion (how it will be sit­ting when poured). The ver­ti­cal sur­faces must have at least a 2-de­gree draft, and the base must be wider than the top. This helps in the re­lease of the part. The other is­sue to be aware of are the un­der­cuts. On some parts, like our frame, this can’t be avoided. To get the part to fit the car, there are go­ing to be un­der­cuts. This is al­le­vi­ated through a two-part mold and a re­mov­able cast­ing base called a “fol­lower” that al­lows the top side to be formed, then the base is re­moved so the other half of the cast­ing mold can be formed.

The bulk of the work on this project is done with medi­um­den­sity fiber­board (MDF) and body filler. The de­sign and build process is time-con­sum­ing, but it’s well worth the ef­fort. Us­ing the orig­i­nal frame as a guide, we built a rough copy from MDF, specif­i­cally the an­gle of the frame rel­a­tive to the door glass and the tails that run into the door­jambs. Ev­ery­thing else will be al­tered.

We built the frame us­ing su­per­glue and brad nails. You want to build the frame base as sturdy as pos­si­ble, as you will be re­mov­ing and in­stall-

ing the piece nu­mer­ous times. The orig­i­nal glass was an­gled at 56 de­grees; we don’t want to chop it—the orig­i­nal height is about right—but that an­gle is too steep, so we pulled the base of the glass for­ward 2.5 inches, which added 6 de­grees to the rake of the glass (50 de­grees to­tal rake). For the glass to be at the same height off the cowl, the glass will need to be length­ened 1 inch, so this is sort of an “anti-chop.” We built an ana­log for the glass it­self with ¼-inch Ma­sonite and used that to create the ac­tual glass sur­round, which was made with 5/8-inch MDF. Us­ing su­per­glue and wood blocks, this piece was po­si­tioned and glued into place.

Once the skele­ton was built, it was time to start the styling. You can fill in the gaps and make a blocky frame, or go crazy and make ev­ery­thing swoopy. We opted for the lat­ter. For this part of the process, we used a com­bi­na­tion of body fillers, in­clud­ing Dura­glass, which is fiber­glass­re­in­forced body filler, and stan­dard light­weight body filler. The Dura­glass is used as the base. This stuff can be ap­plied thicker with­out wor­ry­ing about crack­ing, and it is very strong.

Once the de­sign was com­pleted, the frame was prepped for cast­ing and sent to the foundry. The cast­ing process took about a month. The foundry built a cast­ing frame called a flask and used a process called bonded sand-cast­ing. Un­like green sand, which is fine sand mixed with oil to keep it

01] The orig­i­nal wind­shield is plain and bor­ing. It has no style and does not fit the rest of the body. Time for it to go.02] We re­moved the frame and laid it out on some strips of medium-den­sity fiber­board (MDF) and traced the shape onto the boards.03] The cowl piece has to match the orig­i­nal frame, so we mea­sured the orig­i­nal and trans­ferred that to the new base cowl piece. Even ½ de­gree off can wreck the fit­ment to the door glass.04] The frame has sup­ports that run through the door hinges on the cowl, so we recre­ated those with strips of MDF and shaped it to match.05] The frame base was laid up with notched pan­els. This adds strength to the over­all piece.06] The new base matches the orig­i­nal an­gle and fits the cowl well.

07] We cre­ated a pat­tern for the glass and marked a board with the shape. The line in the mid­dle is where the wood gets re­cessed with a router and a rab­bet bit.08] This be­comes the wind­shield-frame glass form. We added ¾ inch around the glass pat­tern for a re­veal.09] Keep­ing the top of the glass in the same po­si­tion as the fac­tory frame, we set the base for­ward about 2.5 inches, which gave us the 50-de­gree rake we were af­ter.10] Once the base skele­ton was formed, we started lay­er­ing on the filler. This is all Dura­glass for strength. We used mask­ing tape on these voids, placed on the in­side of the frame to keep the filler from fall­ing out of the skele­ton. We will body­work the in­te­rior frame later. This process took sev­eral days to get the look just right.11] The in­te­rior of the frame is pretty sim­ple; you can also see the glass chan­nel.

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