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body weight

PostPosted: Fri Jul 26, 2019 7:21 pm
by GLB
I was curious, thought some of you might be also. Weight of S 1 with bumpers but nothing else. Body is painted and polished but other than bumpers has nothing else attached to it. Total weight is 248 lbs. That makes weight with bare chassis 332 lbs. Finally ready to start reassembly. Gary

Re: body weight

PostPosted: Fri Jul 26, 2019 7:30 pm
by GLB
forgot to subtract weight of board supporting body on scales. It was 10 lbs, so correct weight is 238 and 322. Hate getting old. Gary

Re: body weight

PostPosted: Fri Jul 26, 2019 8:19 pm
by nmauduit
thank you.

Did you sand off the paint to bare gelcoat before applying the new paint (please comment if you will, e.g. thickness of primer, layers of paint...) ? also, would you weight the bumpers so that one may substract them?

for comparison I have in mind the new bodyshells one can buy (bare gelcoat), usually as "superlight" circa 41.5kg, light circa 55kg, standard weight around 72-78 kg iirc

Nic

Re: body weight

PostPosted: Fri Jul 26, 2019 9:33 pm
by GLB
rear bumper 3 3/4 lbs, front 4 1/4 lbs. hence total body weight 230 lbs. about 105 kilos if I remember my conversion factor. Bourne body, hence some paper rope under nose. Body stripped of all gel coat. deck cloth ( a very fine almost translucent woven cloth) over entire body, wet out with epoxy resin. I feel it prevents any future surface cracking and eliminates pin holes, plus is water proof for future wet sanding. No bondo, any fine filling done with microballoons and epoxy, very light and inert, no shrinkage. epoxy primer surfacer as needed, several coats sanded flat. one coat of sealer, followed by three wet coats of polyurethane single stage. sanded to 3000 grit and polished. The body was very rough and lots of holes filled, over 150, large fender flairs removed and replaced. No effort was made at lightness, only for a straight, sound body. I can't guess at weight of finishing material, but it took forever and most of the undercoats are probably on the floor. but I think it looks good. Also the inner fender wells are painted body color and there is no undercoating on the car. Under bonnet and boot are painted grey to match grey Bourne resin where holes were filled. underneath floor boards and tunnel is just original grey resin. Gary

Re: body weight

PostPosted: Fri Jul 26, 2019 10:42 pm
by nmauduit
well, thank you and congratulations, that is quite some work and you certainly deserve to enjoy the car now...

Re: body weight

PostPosted: Sat Jul 27, 2019 3:23 am
by bitsobrits
Is the yellow car in the background a Sunbeam?

Re: body weight

PostPosted: Sat Jul 27, 2019 4:45 am
by GLB
yes. It is a series on 1960 Sunbeam Alpine. No engine or trans but otherwise complete. Never hit that I can tell. A project for later. Not economical but something to keep me occupied.

Re: body weight

PostPosted: Sat Jul 27, 2019 6:28 am
by Frogelan
Very interesting post, thank you.

When you have time, could you also let us know the weight of the body panels please ?

With respect to "advertisesd" weights of bodies, I think there are probably quite a few differences in the suppliers figures and it would be interesting to have the breakdown!

When I get enough cash together to order my body, I will endeavour to do this.

Andrew

Re: body weight

PostPosted: Sat Jul 27, 2019 8:31 am
by GLB
lying in bed tonight thinking about my body weight, I could not believe my body was that much heavier than the 75 kilos quoted. fortunately I took pictures of the balance weights. One was in fact 98 lbs, the other beam had weight values etched on both sides of the beam, I read the value from the back side and the weight was covering 150 as well as the correct 100. I feel very foolish but from my photos of the beams the final correct weight is 198 lbs with the board and bumpers. 180 lbs just body. 81.8 kilos. I hate to put my foolish error on display to the smarter group but feel better now. I will weigh the other panels tomorrow.

Re: body weight

PostPosted: Sat Jul 27, 2019 8:35 am
by trw99
Interesting fact came out of Harry Metcalfe?s Sprint in London YouTube (see another thread), which I had not heard before, but given the source quite believable.

Mick Miller told Harry that during the financially sound years at Lotus, Elan bodies were laid up thicker, using more materials, than during leaner years. Thus S3 bodies tend to be heavier than Sprint bodies!

Tim

Re: body weight

PostPosted: Sat Jul 27, 2019 12:09 pm
by 661
GLB wrote:lying in bed tonight thinking about my body weight, I could not believe my body was that much heavier than the 75 kilos quoted. .


#Me Too

Re: body weight

PostPosted: Sat Jul 27, 2019 12:35 pm
by elanner
Page 106 of Robinshaw & Ross shows Lotus' contract with Bourne to build the early shells. It quotes a weight of 199 lbs (+19 lbs for the hardtop). This seems to include doors, boot lid, bonnet, & headlamp pods because they are not mentioned separately.

Many years ago I read an article about the development of the S3 that mentioned there was a goal to reduce the amount of fiberglass used for cost/weight reasons. Apparently they overdid things to the point that during development a road tester stamped on the brakes and pushed the pedal box through the fibreglass bulkhead. Presumably the idea was abandoned....

We can all measure the weight of the bonnet (an S4 with Stromberg bulge is 13.5 lbs with my ancient spring scale), while a bare S4 door shell is 11 lbs (again, with my scale).

Nick

Re: body weight

PostPosted: Sat Jul 27, 2019 5:30 pm
by GLB
still feeling foolish, here are other weights
Body 180 lb
bumpers 8
boot lid 8
bonnet 12.5
headlights 3.5 (both)
rt door 13.5 ( doors have pivot pin castings and pins in place, door gap set before paint )
lt door 13.75

total 239 lbs ( 108.5 kilo)

Re: body weight

PostPosted: Sun Jul 28, 2019 5:07 pm
by richardcox_lotus
When Miles Wilkins painted my Sprint back in 2013, he remarked upon completion that it was a very thin shell, probably for the reasons mentioned above - a reduction in build material for financial reasons !

Re: body weight

PostPosted: Sun Jul 28, 2019 5:41 pm
by el-saturn
i know this is maybe asking too much; but do WE know the wallthicknesses in some critical (bobbin and chassis/body bushes etc.. and less critical areas (only body) per drawing - we do know the appr. surface and i'd say unloaded areas are at least 2mm thick (here we don't talk about resin/fiber ratios!!) - or does anybody have a laminating plan where they prob. don't determine the amount of resin?!? i bought my new lotus s3dhc body as a lightweight and not race or anything - but that was in 1983 or so! sandy