Woodwork

[dictator27]

In the topic about least favourite restoration job I said woodwork.  That topic has generated a question about what else - woodwork.  The wood in my 27 Dictator sedan from the centre doorpost back in the roof and the floor is in very good original condition.  From the doorpost forward however, the wood is gone.  Someone replaced the roof wood by peeling back the roof fabric, cutting off the wood just forward of the doorpost and replacing it with crudely installed 2x2's.  The floor wood was almost totally rotted away.  The cowl was supported by short pieces of 2x4 jammed under it.  My question is this: What is the best way to connect new wood to the existing wood?  I don't want to replace any more wood than necessary.  Any and all advice greatly appreciated.

 

Terry

[bryankazmer]

my first thoughts would be finger joints or pegged lap joints

[dictator27]

There are finger joints above the rear door hinge pillar about 34 inches from the point where the wood was cut.

[Mark Gregory]

I agreed to your response about In the topic about least favourite restoration job I said woodwork.

Here is an example of some of the stunts I had to do to repair my door wood.

I will look for a picture of what I did for my roof rail work also.

 

[3macboys]

I'd go with a scarf joint if you are fitting it in between other joints and then glue it up with a good quality epoxy such as West Systems

[chistech]

I would recommend you post some pictures of your wood if you want good advice. If the sills are rotted away from the center door posts forward, you need new complete sills if you want your car right. Doors are adjusted by shimming at different body mounts and bending the main sills to get the doors correct. You cannot bend spliced main sills and get your doors right in most cases. By your description this a four door car and it’s mandatory to have a solid frame front to back. It sounds like you car leaked at the front roof and it’s common to have the majority of the front wood rotted away. The roof commonly has both inner and outer side rails. Then there is a front header along with an upper front roof piece mounted to that front header. The roof inner side rail is usually under the edge of the roof metal and the vinyl roof gets nailed down into this wood. You will never get a leak proof roof is this wood is bad in any areas. Along with this you will have roof cross bows and roof slats nailed to the bows. I have replaced lots of wood pieces and done total rewooding depending on what was needed. 
      I’ve used scarf joints (a staggered, two level joint), diagonal cut joints, lap joints, and tenon joints where each joint was appropriate. Original wood has to be evaluated really carefully especially in a car that has badly rotted wood in some places. Often wood is missing or in bad shape because of dry rot, mistaken for wet rot. Dry rotted wood can be structurally bad but appears in usable condition. Some pieces can be broken out because of load, being stepped on, etc., and others pieces tucked away still present, but structurally weak. Wet rot is usually in areas where water contact is normal. Many cars will have the lower cowl wood, rear body wood, and the rear cross sill wood, under the trunk or rumble seat, rotted because of water constantly soaking it. The wood often has a black color and pieces missing where dry rot often has all the wood intact and whiter in color.
     I would google Jim Rodman’s Antique Autowood site and view a few of his exploded drawings to get an idea of how your car Was built. A studebaker sedan appears to be very similar to a GM car which I’m familiar with and looking at photos of a dictator I’m pretty sure the wood framing would be very close to the same.

Edited June 10, 2020 by chistech (see edit history)

[TAKerry]

Without seeing the wood, I would suspect a lap joint would be best. Done correctly  it will be almost as good as original. A good waterproof wood glue ( i use titebond for everything) is sufficient. No need for fancy glues. I dont know car joinery, but have been woodworking for 40+ years, and building fine furniture for half that time. In furniture work a well executed joint does not need to be pegged. They dont add any more strength to a good glue joint. Also, no need for fancy glues, throw away the gorilla stuff. Again, waterproof tightbond is all you ever need. I know a fellow in the furniture business that is one of the best in this country. His furniture is literally in the White House. He is multi generational and the only glue they have ever used is white elmers. 

[Guest]

17 hours ago, 3macboys said:

I'd go with a scarf joint if you are fitting it in between other joints and then glue it up with a good quality epoxy such as West Systems

A friend of mine used scarf joints to replace rotted wood on his Oldsmobile.  Everything forward of the mid point above and below the front doors was gone.  It took him a month or so.  He drove the car for over thirty years before he died.  The new owner has been driving it for over twenty five years with no problems.

[dictator27]

Thanks to all that have responded.  I took a closer look at the wood and the sill wood does have dry rot in it.  The sills are two pieces, one on top of the other.  Bottom piece is 6 inches wide and 1 inch thick at the widest point. Top piece is 4 1/4 wide and 1 inch thick at widest point.  They are screwed. together.

The remaining roof rail wood is in good condition.  They are also two pieces, one on top of the other.  The lower piece is 2 1/4 inches wide and 1 1/4 inches thick.  The upper piece is 4 1/4 wide by 1 1/4 thick.  They are screwed and bolted together.

There are actually two finger joints on each roof rail, the previously mentioned ones over the rear door hinge pillars and one on each side directly above the centre door post.  I don't know if there were any more further forward.   I have enough oak here to do everything, but I understand oak is not the best choice?

Edited June 10, 2020 by dictator27 (see edit history)

[Mike "Hubbie" Stearns]

If it were me, I would just replace all the wood. I know it’s a lot more work and cost, but would give you a better end result. 

[Gunsmoke]

When I decided to rebuild my 1931 Chevrolet coach back in 2008, the primary reason for a re-build was bad wood. Doors had a 1/2-3/4" droop, turns out front posts were shot. 2 major areas needed attention, front and back. Up front, both front door posts, the front half of the main sills, the ends of the roof side rails and the front roof header were shot or crudely fixed. In back, the rear roof cross member, and about 16" of roof side rail was badly rotted. That's about 35% of the wood. I realized it could be done without de-skinning the entire car, so that's what I did. I have the required woodworking gear, and used ash for structural members, and poplar for non-structural.  Generally used scarfed joints with glue and in some cases through bolts and T-nuts. For the main sills, I butted new to old and used 1/8" steel plates top and bottom to create a solid job. Here and following are a few photos of how things went together. It took a lot of fitting to get everything close as many of the old pieces were too far gone to be much help as patterns. I did look into buying a full kit from Rodmans, but felt I could do it my self for the cost of $300 of wood. Only pieces I would buy if I had it to do over is the front door posts which were very complicated shapes. I'll post a series of photos for those who are contemplating doing it themselves. This set of 4 show new front sills spliced to original just ahead of door post, and extensions put on roof side rails. 

Edited June 11, 2020 by Gunsmoke (see edit history)

[Gunsmoke]

This series shows how I replaced the rear roof cross member. In order to avoid disturbing the steel brackets shown, I created a 2 piece tapered end, pre-drilled and fittted with 3/8" T nut installed flush on upper side, then simply slipped the wedge in first, with glue on it, then the long top piece and put 3/8" countersunk machine screw up through bracket and bothe wood pieces.  Notch in upper piece is to recieve the roof side rail. 

[Gunsmoke]

Photos of rear roof area with old wood removed.

[Gunsmoke]

A view from top of rear roof cross member, note the short added piece necessary to house the tenon for a new cross slat. Floor framing under front seats accommodates tool tray @ photos showing original braces at new front door post, and at original rear door posts. 

[Akstraw]

Ash was the structural wood of choice for making auto bodies back in the day, and I believe is still used today by the Morgan Motor Company in new cars.  White oak has somewhat similar structural properties, and both have good rot resistance.  Oak has high tannic acid content which, over time, will cause screws to discolor and eventually corrode faster.  The two machine similarly, and both are generally available.  I have worked quite extensively with ash in antique auto body repair.

 

While not looking to pick a fight with those above who recommend long-standing adhesives, I have found modern structural engineering epoxies perform excellently in this application.  An auto body must withstand a much more rigorous environment of stress, vibration, temperature variation, and flexure than most furniture items.

[chistech]

17 hours ago, dictator27 said:

Thanks to all that have responded.  I took a closer look at the wood and the sill wood does have dry rot in it.  The sills are two pieces, one on top of the other.  Bottom piece is 6 inches wide and 1 inch thick at the widest point. Top piece is 4 1/4 wide and 1 inch thick at widest point.  They are screwed. together.

The remaining roof rail wood is in good condition.  They are also two pieces, one on top of the other.  The lower piece is 2 1/4 inches wide and 1 1/4 inches thick.  The upper piece is 4 1/4 wide by 1 1/4 thick.  They are screwed and bolted together.

There are actually two finger joints on each roof rail, the previously mentioned ones over the rear door hinge pillars and one on each side directly above the centre door post.  I don't know if there were any more further forward.   I have enough oak here to do everything, but I understand oak is not the best choice?

Using two 1” thick boards to make up the sills and other parts like deck rails was the common practice when these cars were built. They were glued most like with horse hoof glue and that is why many sills are de laminated today. The old glues just deteriorated over time from the moisture. The wood also had a preservative/insect repellant applied to it. Most people replacing wood often mistake the green color found as mold or moisture but it’s actually the remnants of the copper arsenic used. On my exact restorations I use copper naphthalene which is the closest product to the CA and not only mimics the preservative/insect properties but also mimics the green color.  If you do cut any of this wood to make a joint use a good respirator as a precaution while cutting, sanding, and cleaning it up. One would think what’s left of the CA would not be that harmful but why risk it. As far as the wood, I found the oak is much more sensitive to the moisture in the air and will swell much more than the ash. I use ash almost exclusively for all my wood repairs. I included some pictures on my 32’ Olds deck rail bottoms that I scarfed in new pieces. Because the deck rails are two 1” pieces laminated, making a scarf joint is actually quite easy. The joints were thinned epoxy glued and screwed. Slightly Thinning the epoxy helps it penetrate the wood grain better.

[dictator27]

I took a look at Rodman's Autowood site.  Wow!  I knew GM products of the day had a lot off wood in them, but didn't realize just how much.  By comparison, I have no vertical structural wood at all, just the roof, roof bows (no slats), sills and cross sills.  The closest things to vertical structural wood are short lengths inside the centre door posts which support the front seat back.  This has been a very informative topic.  After many years of procrastinating, it is time to put my limited carpentry skills to the test (and my very basic woodworking tools) to work.🙂

Edited June 11, 2020 by dictator27 (see edit history)