Dynatech MT4 titanium 'Rebuild'

paininthe":2amgeosv said:

Just being doing a bit of research with the coefficients of linear expansion of the various materials involved in these frames. I would say powdercoating is a NO,

Titanium has a low coefficient of linear expansion which is equal to 5.0x10-6 inch per inch/°F, whereas that of stainless steel is 7.8x10-6, copper 16.5x10-6, and aluminum 12.9x10-6.

So nearly x3 much expansion of the Aluminium v Titanium.

The expansion alone of the two differing materials would pull (or seriously weaken) the joint that the risk is not worth it

Click to expand...

i used to work at a raleigh dealer and when i was reading all the bumf about the new dynatech range it stated that the process of bonding was not a completely cold one it was just a lot cooler than welding or brazing but the actual epoxy setting process was done with heat ,i cant remember exactly but i was between 140 degrees and 240 degrees f , compered to well over a thousand degrees for welding and a bit less for brazing

i think maybe the expansion would compound the joint tighter not pull it apart
as would have been the case when originally fired at birth

i guess its wide open for debate and if i can fix this hole i may just take the experiment on and see what happens
it would be a funny sight to be sat on top of a pile of titanium tubes on the start line

update

its about time i updated this thread so here's how far ive got since last post,
it coming along nicely and im quite pleased with it too ,
first of all i had the frame repaired at my local fabricators , he did a great job and you would never know that there was any hole there unless you knew about it ,there was a small crack too that was coming off the hole he said and so he drilled a new hole to stop the crack running and then put over and in both holes a peice of steel (the seat stays on the MT4 are mangmoly steel) and ground it back to perfection , he charged me a fiver ...come on ! in ten minutes he had just saved my baby from being writen off so i gave him a tenner .
from this

to this


will the repair be strong enough ? pottering around town he says no problem but hardcore off road only time and riding will tell .

next up was the paint job ,well i wanted to bring out the elements of dyna mt4 frame and demonstrate hidden potential for what i feel is one of the nicest mtb frames of old , and ,i was also intrigued with the talk of DYNA's and powder coating in the forums, that is i wanted to put to the test the powder coating fearmongerist crowds theories that where chanting "DONT DO IT YOUR LADY DYNA WILL DIE IF YOU DO " , so naturally for my inquisitive natrure i did do it ......TWICE !
i have to admit i didnt go into it balled headedly , i used a bit of common sense which for me isnt that common at all but whaen i was repairing the brakes bosses on the top tube i did so with a product called JB WELD (since 1969) it sets as strong as steel and resists temps up to 600F with this and with the knowledge that dynatechs indeed where being cured in a low temp oven at birth, i asked myself why would raleigh use an inferior epoxy resin than the one you can buy for £4 of ebay also the steel worker who deals with powder coat every day looked at the original paint and thought that it was PC with speccles in it and thirdly the powder coat guys rubbed some stuff (thinners i think )on the paint when i took the frame in for the first time and they said it is not spray paint but the effect they have not seen in powder before ,so who knows it could be original special powder coat that was baked on at the factory

first time it went in the oven the lads at ace powdercoating in hindley didnt do a great job of masking the alloy bits i had pointed out for detailed masking
so the frame came back to me not at all how i wanted it with not just bad masking but bits that had been masked that i didnt ask for , someone wasnt listening :roll: ,
this is after the first powder coat and before the second ,you can see the bit they masked wrong at back of seat tube

another bit they kindly added to the unwanted mask list

frame before second bake with my masking


but i liked the guy as a loveable rogue and he said for me to mask it up and put it back in the oven a second time which went well
patches of previous errors fixed



NOTE: i greatly recommend doing your own masking if it is required as no one else shares your love and care for the bike full stop , no offence to second and third parties intended.

i also tested the bikes lug/tube strength after PCing by trying to sprise it apart with foot and arms with no movement thankfully , i feel confident with the frames strength even with the double dose of 200c treatment it has had this week , but riding off road is different and will test it to the max ,so indeed when it is finished and been bullied for a bit i will update the results on strength so for now this subject is on going ,

keeping with the PC subject i will add this information for anyone thats as geeky as i am .
ive been keeping my eye on the weight of this build and want to keep it below 21 lbs if poss so in my anal endeavours i weighed the frame and forks and these are my conclusions :
frame weight before paint strip 1950g weight after 1710g thats a whopping 240g of paint from the raleigh factory
now
frame weight after two bakes of powder coating is 1760g ..so much for the powder coat weighs 300 grams-ish myth i have read in one post somewhere here ,well this im really pleased about because it means that i gain a full half pound back from my weight watchers allowance YeaY !
before PC

after 2x PCing




moving on now next up i have built the wheels which are xtr m970 v brake hubs on stans ztr355's with revolution spokes and black nips , now im not going to post how i built the wheels because others have done a great job of that already on the forum which i dont think i can make any better so instead i will show you a little tool i used and it simply brings the spokes up to tension quickly ,evenly and should leave you with a wheel that has very little radial errors (up and down) before you start to go into the last phases of tension and truing ,its just a screwdriver filed down on both sides to leave a prong like point in the middle ,1.5/2mm long ,to use it just turn the nips until the spoke pushes the head from the flat head groove do it to all spokes till the tool no longer works on any spoke and your done and ready to true ,simple heres a pic


and heres a jig that i rigged up out of an old drum stool with the stool seat tube removed and the forks put in upside down an use the stool tension adjuster to lock the fork secure , and for the rear wheel i duck taped the frame to the fork ,use a set square and universal joint light bracket for the reference it works well and is accurate enough ,plus the whold jig rotates to make working really easy

i dont know if i am allowed to do this but to make this thread a bit more educational i have also put this ebook on rapidshare for any wannabe weel builders, beginners or advanced its a good read

http://rapidshare.com/files/448794798/B ... ilding.pdf
i didnt write it by the way



so finaally i will show you the frame now as it stands ,i have teased you for long enough so here she is without parts yet ,im waiting on tools to arrive

before

after








thanks to chaser (the authority) for directing me to the decal man, i got them from Gil_M a forum member and they are really fab looking and trust me hes good and quick to meet your needs on decal specs , however the decals are fragile especially on dyna techs with the little whisps on the lettering that will lift if not extremely careful, MTBing and careful.... hmmm i dont think they will stay good looking for long if you dont clear coat them after fitting them ,ieven though you fit them as whole words/decals the lettering within the words are individual , i feel a one piece decal obviously would be allot harder wearing but hey beggers and choosers springs to mind ,since youve more chance of finding rocking horse shit than dyna decals clear coat is not a bad trade offf , as any one done this with Gil's decals i would like to know which clear coat to use or not to use please?

i havent seen another dynatech like the one i am working on with dull polished lugs and alloy bits/trimings ,if you know of any that i may have missed here at the forums i would love to see how others turned out so let me know please

il make another final post when its full assembled and tested
for now taa-raa

ps
o would like to thank Gil_m for swaying my decision on the decal colour flat silver is an amazing match for dull allu and powder coat chrome it really is the beez bloody knees , taa

Great job and well done. I like the work you've done with the stripping and powdercoating.

I've spent many an hour pondering this whole curing and bonding thing and glad that you've done some practical testing for us all.

Thanks and get some elbow grease into polishing those lugs!

hey man,
elbow grease... dont make me work anymore please stop putting teasers in my brain ,
no thats what i had in mind at first but i think i may just leave the lugs as they are ,they seem to match nicely with the chrom powder coat forks but it means that i will have to dull down the drrt research stem too to fit in (have to rub off the decal with no replacement), on the other hand polish lugs and get the forks electro plated instead to match,
aaghh .. do you see what youve done now ! il end up escalating this till its unrecognisable and getting a shocking pink with polca dots frameset idea

and im glad to be of help to anybody whos had the powder or not to powder question going on , but i have to stress i have not give it a punishing off road yet so before i can say PCing is safe this will need to be done and reported back here , i dont want to be responsible for any accidents frames falling apart unless its my accident and with my frame :shock:
im fairly confident it will be just swell thou

That looks fantastic, well worth all the effort.

Nice transformation there! when are we going to see it finished?

I sanded my dyna-tech frame down for fear of it falling apart if I used any other method, but now I think I'll look at getting it powdercoated later this year

thanks for hte comments
hopefully get it completed by next weekend ,
i used paint stripper and a stanley blade to get rid of the paint

if anyone can help i need a silver alloy brake booster for the back brake as lite as possible 50g ish
ve got most parts but if anyone got one lying around it would help

and can anyone tell me what size titanium bolt i should be looking for the mt4 seat post collar ??

oh and does anyone have such thing as a 'dirt research' decal for a stem ,it a long shot but there i go

are there any decent lightweight pedals (non-spd) i can ebay for , high quality light cage pedals retro or new, i cant for hte life of me remember what was any good 15 years ago , i have bought some of the new BREVm cnc jobs but they are really narrow where the strap goes through and dont think they will work with rugged footwear so they are going back to evans , any help on this subject ?

a wanted luxury item i would like is a pair of x-lite titanium L bar ends from 90s

thanks

help please

build is almost done, seat bolt and other bits came this morn, i was just gonna go out for a spin this arvo but errr......

damn it ,ive just snapped a titanium bolt inside the frames threaded seat collar :shock:
any one else had to deal with this ??
what did you do to fix it please , the least amount of butchery would be nice ?

DYNA

Awesome, i've been in the process of converting a dynatech Ti racer for about 4 months with endless searches of the web for advice on PCing bonded frames, just wanna say thanks, gonna get it sandblasted with a glossy clear powdercoat. Will update with pics.

Cool

Good stuff

Perfect colour choices

Nice trousers and a groovy happy face on your weighing machine

Great thread, I read all of it