FT: Frame (Twin) Seat-base wood thickness

[Flyinglow]

I need to make a new seatbase!
Can anybody advise me what the correct thickness of the wood is?
I think Know They Beast quotes 7/16" which seems a bit thin to me, plus how much smaller should the perimeter be compared to the foam.... My new foam is actaully about 1" longer than the orignal I have removed.

 

[vibrac]

7/16" ply is not on its own PR1A/3 framework and carries all the weight and distributes it PR1A/4 Hoop and PR1A/2S rear hump sorts out the rear
all parts shown separately on

1. Twin
2. Frame
3. SEAT COMPONENTS in the spares company shop (including the wood base)

 

[bmetcalf]

I used nominal 1/2" plywood, which is really about 15/32". Good info here: https://www.vincentownersclub.co.uk/threads/plywood-seat-base.10781/

 

[Bazlerker]

I used 1/2” marine grade plywood the last time I made a seat base and painted it on both sides before assembly.

 

[bmetcalf]

@Monkeypants has some opinions on marine-grade plywood, if I recall correctly. Although it might have been @Robert Watson

 

[Flyinglow]

Thank you all for the replies 1/2" it is going to be then

 

[Cyborg]

@Monkeypants has some opinions on marine-grade plywood, if I recall correctly. Although it might have been @Robert Watson

As far as I know,some of the big box stores sell what they refer to a marine grade plywood, but technically it isn’t. The glue is likely just fine for a seat base. Marine grade shouldn’t have any voids….which increases the cost. If you are paying for true marine plywood, you’ll notice the difference. Either a good paint, or you can brush on a couple of coats of saturating epoxy. It’s 50% epoxy and 50% solvent. Soaks in and basically hermetically seals the wood.
There can be quite difference in strength among the different versions of 1/2 plywood. The saturating epoxy will add a bit of strength.

 

[Marcus Bowden]

I made mine from 1/4" duralumin in 1965 fitted seat stays then moved them out 1/2" and fitted seat stays to the back of s/s footrest plates never touched it since apart for putting on ne seat covers, put a 3/8" wood base on the aluminium the first time I recovered it a screwing s/s 1/4" strip around the side would take too long so used monumental staples into the wood and the tubes out the back I slide on my four panniers held by 4 R pins and the two small panniers we sit on and eat off the big ones and the stoves sits on the s/s frame. lived off the bike ten weeks in NZ in 1995. Still the same.

 

[vibrac]

If 7/16" was good enough for Eddie Stevens its good enough for me. Bananaman is a special case he has to have the carry capacity for a Series A flywheel two Burman gearboxes and a cylinderhead, (you cant pick up too many spares on your travels )

 

[Albervin]

I made my new seat base from 7/16 marine ply after I found my 1949 seat base had delaminated!! I cut the new base very carefully and rounded all edges.I then liberally coated it with Penetrol wet on wet coats after I drilled the holes. I re-used my original Dunlopillo foam which overhangs the base by about 1/8". All metal parts were soda blasted and epoxy coated.