PVC or PTFE for body lift blocks?

[lord_flashart]

Hi, I have had a few ideas with making my own body lift kit as I am a Manager at a fixings company and I just realised I can get the materials for making my own lift blocks as well as the bolts.

I am looking into incredibly affordable PVC or PTFE for this project. Anybody have any ideas whether these would pose a problem over polyurethane which seams to be the material of choice? I have some samples coming into me anyway so I can test them and see what happens. They are as resistant to chemicals, diesel, petrol, heat etc and are hard wearing excellent machanical properties so I should be covered.

The bolts are easy enough to supply and bumper plates and rad drop brackets are easily made too.

Anyone with any experience with these materials or know of any reasons why they should not be used?


Thanks,


Ray.

[Sancho]

I would have thought PTFE was a bit soft and PVC a bit liable to cracking under impact. My personal choice would be aluminium.

[lord_flashart]

There are different grades of both and they are apparently both very hard. This is the same for polyurethane, cheap bushes are very soft and decent ones can be made very hard. I have also specced with aluminium so I'll see what happens when the samples turn up.



Ray.

[MattF]

There are different grades of both and they are apparently both very hard. This is the same for polyurethane, cheap bushes are very soft and decent ones can be made very hard. I have also specced with aluminium so I'll see what happens when the samples turn up.

Hardness and strength are two completely different beasts. No good being rock hard if they crack under the smallest bit of stress. Aluminium would be my personal choice.

[Gamedawn]

A lot of the commercial lift blocks are made of "plastic" but they tend to be of high density polyethylene. As I'm an electrical engineer and not a materials scientist I won't try to explain why

[Apache]

Thought they were generally nylon!

[GRASSMAN]

Hi guys,

I've worked in engineerinng "plastics" for over twenty years.
PTFE can be very costly,
PVC will become brittle after a while,
There many types of nylon but it absorbs water,
and also becomes brittle,
UHMWHDPE (polyeth) is a good choice use 1000 grade,
and does not degrade, (think carrier bags)
Alluminium would be my first choice tho.
Hope this helps.

Gman.

[Albannach]

Isn't it Delrin (may be a trade name) that the 'plastic' blocks are made of?

Aluminium would be my choice too.

[GRASSMAN]

Isn't it Delrin (may be a trade name) that the 'plastic' blocks are made of?

Aluminium would be my choice too.

Hi mate, enjoy your hols?

Delrin is a trade name for polyacetal, it's quite hard,
but brittle when cold, used in the food industry mostly.

Gman.

[Albannach]

Hi mate, enjoy your hols?

Delrin is a trade name for polyacetal, it's quite hard,
but brittle when cold, used in the food industry mostly.

Gman.

We used to use it years ago in the suspension of a modded 280ZX, ws way too harsh though so we took it out.

Holiday was good thanks, burned myself though. At the moment I look like a grey haired lizard!

[lord_flashart]

Hardness and strength are two completely different beasts. No good being rock hard if they crack under the smallest bit of stress. Aluminium would be my personal choice.

Hi guys,

I've worked in engineerinng "plastics" for over twenty years.
PTFE can be very costly,
PVC will become brittle after a while,
There many types of nylon but it absorbs water,
and also becomes brittle,
UHMWHDPE (polyeth) is a good choice use 1000 grade,
and does not degrade, (think carrier bags)
Alluminium would be my first choice tho.
Hope this helps.

Gman.

MattF, I'm an engineer myself but just haven't done too much with plastics, what I have seen first hand is people fitting stainless bolts to their brake calipers and stems on mountain and motor bikes and then having their brakes and bars flyoff at speed! It may have taken more time but learning about material properties at college was better than a high speed lesson from "Professor Face-plant" as you grind your cheeks on the tarmac!


Gman, UHMWHDPE is also available from our supplier pre-cut to length and I can have the bolt hole bored too and at a reasonable price so I'll get some firm quotes on that.

I am sorted for the bolts, the rad drop brackets and bumper mount brackets will be easy and cheap to make so block material is all that is holding me back at the moment. I could, if the quotes come back as they were earlier, be able to make simple, cheap and good quality 1" and 2" lift kits within a few weeks.

The only few things I need to check are;
1. Is anything needed to be done to the steering rack?
2. Will brake lines need to be extended?
3a. If you are on a manual box does the gearshift NEED to be extended or can you just get used to the stick being 1" or 2" lower? (That's for people who have no access to welders or are too inexperienced or too scared!)
3b. If you extend the shifter does it make the 'throw' of the stick hugely different or awkward? (Do you have to pull your hand out of the stereo and onto the back seat changing from third to fourth and do first, second, fifth and reverse mean you have to 'touch up' your passenger or yourself during the journey? This could be particularly awkward whilst dropping your Mum home after tea and cakes!).
4. Can you increase your tire size with a 1" or 2" body lift and if so, what size could you run? Would the 1" or 2" kit be recommended with any lift in suspension in order to enable your fat tire choice to clear the bodywork and if so what sizes?



I understand that most people attempting a body or suspension lift would already know the asnswers or be fully prepared to expect to do something else including even fabricating brackets etc. (there are no kits or sites I have found that sell these kits that give ALL of the info, I have got most of it together from different places to make one big project) but there are plenty of people who are fully prepared to do the work, they just don't have all of the tools for fabrication but if almost everything was supplied, pre-fabricated and with detailed instructions including what to do with the steering rack and gear stick (if anything) AND what they expect to acheive with tire choice etc. they would have no problem with a jack, somes spanners and this kit to do it themselves.

Bit of a massive post this one but I want to get everything in place as soon as possible.

Please le me know if I am taking this too far but I do like to do things properly and I hate it when I buy something only to find out after it's too later that there are things I needed to do before I or other things I need to do after to use it!


Thanks to everyone who has helped so far and thanks in advance to everyone who will help in the future,

Ray.

[lord_flashart]

OK, PVC is no good.
PTFE seems not too bad but I am gonna test it to death and see what happens.


I'll let you know........



Ray.

[Albannach]

[quote=lord_flashart;554291]MattF, I'm an engineer myself but just haven't done too much with plastics, what I have seen first hand is people fitting stainless bolts to their brake calipers and stems on mountain and motor bikes and then having their brakes and bars flyoff at speed! quote]

How often have you seen that?

I've been around Motorcycles for 30 odd years and have never seen a brake caliper or clip-on/bar break free.

[lord_flashart]

Quite often; I worked at Damerells Motorcycles in Cornwall for a while and for about 15 years I have been a sponsored downhill mountain bike racer and trials rider so I've seen it happen a lot!

It look slike it hurts and when it's a 3 week old Ducati 888 (with £4000+ carbon and titanium Ducati Racing extras fitted to it) it hurts even more!!

Looked like nice bike beforehand!

[Storm]

Hi just done a 2" lift on my truck maded all the bits up and bolts for £38 all in.

easy job take about 5 hours to make blocks and brackets and fit it all.

http://www.4crawler.com/4x4/ForSale/...BumperBrackets

this helped me with what i needed