Seat Risers

The seat risers are structures that are attached to the bottom of the seat, to give it height, and to fasten the seat to the box.

The first order of business on this mini-restoration project is to remove the cast iron braces, of which there are two on each riser.

Click on any photo to enlarge.








FASTENERS  

Oh, right...fasteners.  Throughout the removal of hardware on the seat I find these little buggers.  They look like carriage bolts, but they are not.  They are step bolts, which have a wider and flatter head than carriage bolts.  Interestingly, while most carriages are put together with a few thousand (tongue-in-cheek) 1/4 inch carriage bolts, these are smaller, #10 to be exact.  Not only can you not find step bolts at the local hardware store, but if you can find them on line, they usually sell in lots of 400-600.  After searching all morning, I finally purchased a box of 100 (I need about 24), along with boxes of #8 and #10 3/4" slot-head wood screws.  I then had to go to another supplier for a box of 100  #10/24 square nuts.

MORE DISASSEMBLY  

The four braces are labeled, dressed on a wire wheel/bench grinder, then buffed a bit with a Scotch Brite metal surface conditioning wheel .  Since these are hidden under the seat, no further surfacing was done.  They were degreased, blown off with compressed air, and hung up for a couple coats of Rustoleum rusty metal spray primer.  They're done for now.

The next step was to strip the paint.  I first tried stripping the old paint with a torch.  That worked really well, but I discovered that this paint is quite flammable, unlike my last project!  I will swap the propane flame for a heat gun.

There was just a skiff of paint on the surface of these pieces, which made stripping pretty easy.  I finished up paint removal with a random orbit sander and an 80 grit disk, then finished up by hand with 80 grit.  Time to go on a major search for repairable flaws.

The worst flaw is a well adhered chip (upper riser, upper right corner) that was probably produced when the vehicle was being assembled.  There was a very small amount of lead type filler in the crack that would have been used to conceal the flaw.  There are a few edge cracks and the ubiquitous worm holes.  The lower edge of the left riser is worn and chipped where it rests on the edge of the box.

The risers came into the house for repairs, because the repair material requires warmth to cure.

DEFECTS  

The major flaw is this chip, which communicates with the bolt hole and goes all the way through at the edge, but is solidly attached.  It appears to have been caused by a hole-drilling/screw insertion process on the upper edge.  There are two screw holes on the upper edge of the risers, and no matching holes in the bottom of the seat, which tells me the bottom of the seat has been replaced at some point.  Generally speaking, rot is a BAD problem in that area.  This makes carriage #4 for me, with rot in the lower corners of the seat. Worm holes are apparent, and the white stuff in the crack is ancient lead filler.  There are a few tight edge cracks, and that's about it.

The repair product of choice is a penetrating epoxy resin.

REPAIRS

The penetrating epoxy resin I have on hand is LiquidWood by Abatron.  It is an architectural product designed to penetrate damaged/rotted wood and restore its structural integrity.

There is a companion product called WoodEpox which is a lightweight putty for filling/building out voids.

The first task is to locate and "dam up" with masking tape, any potential escape routes where the resin might drain out of the damaged area.  There was only one such spot on the upper edge of the one riser.

The rest of the job is a babysitting game.  The resin will creep and soak into the damaged wood until basically, it sets up too much to flow.  Depending on a few factors, this can take forever!  Watch for "dimples" to form in the rounded surface of the resin "bead", and as long as dimples form, resin is penetrating and more can be added.  I use a 3ml syringe with a large bore needle to apply the resin.

LATER...


I babysat this project ALL afternoon.  The resin remained fluid for hours (which is not always the case!) and the wood absorbed tons of it.  As long as it flowed, and as long as the wood accepted it, I kept drizzling it into the cracks.

I ended up putting a small table lamp on the resin to hasten hardening.

While the resin was still tacky, it was time to mix some of the companion product, WoodEpox, and fill any voids that were not overflowing with resin.

The resin acts as a "primer" for the putty, giving it excellent purchase, and the end result should be permanent repairs.

I've created a lot of work for myself by applying the putty so generously...there will be a lot of sanding to do!

That may be awhile, but a little heat will hasten curing.  I think it takes about 1-3  weeks for the epoxy products to attain full strength, but I should be able to sand well before then, as long as the sometimes-fussy resin hardens sufficiently.





AND FINALLY... 

The repairs have cured and excess has been sanded smooth.

The outer surfaces and ends of the risers were then coated with a very thin layer of automotive spot putty  to fill grain and any remaining tiny imperfections.

The spot putty was then sanded back with increasingly fine paper, ending with 220.

The risers are coated with clear wood sealer.

And finally, the risers and brackets are temporarily reassembled.  Now I can quit worrying about the wood warping!

The repairs to these parts are now complete.  They will spend the winter in storage in the office awaiting painting weather!

The next stage will be to remove and refurbish the ironwork on the seat, and on to the seat itself!