Making Sense of Gasket Quotes and Material Specifications
Posted on 05/03/2014 Category: Technical Features
We know you’ve been there – you have three quotes from three different rubber suppliers for a straightforward gasket to be manufactured from neoprene rubber; one of them is quoting 98p each, the next is quoting £1.10, and the third one is asking for £2.68 each. They are all offering neoprene at 3mm thick and they are all quoting for 1000 off. So, do you spend £980, £1,100 or should you spend £2,680 – and why?
The difference in the three quotes may look something like this:
- Company A: Gasket to drg. ABC123456 Rev 0. Material offered is 70sh Neoprene. £0.98 ea.
- Company B: Gasket to drg. ABC123456 Rev 0. £1.10 ea.
- Company C: Gasket to drg. ABC123456 Rev 0 in 70sh Neoprene to BS2752:C70 2009. £2.68 ea
There are three questions you must ask:
- What does the drawing call for, and can you get a concession on the material?
- If you are unsure of the official specification, is there a history of supply, and if so what was supplied previously?
- What type of application is the gasket being used in, and what chemicals/temperatures is it likely to see?
Neoprene manufactured to BS2752 is more expensive – and for good reason; the manufacturing process and ingredients are controlled, the material must meet particular parameters laid out by the British Standards Institute, and the quality of the material is of a much higher standard. Commercial neoprene may, and often will, do the job – opting for a BS grade could simply result in an over-engineered product with an inflated cost – but the properties of a commercial material are not guaranteed, nor are they necessarily consistent between different sheeting manufacturers or even batches and it will not have been tested to the BSI requirements.
It is likely that Company ‘A’ in the above scenario is offering a commercial neoprene, as they do not cite the BS2752 standard in their quote line and have made this reasonably clear by putting it in writing. Company C is definitely offering a BS2752 material. Company B’s offering is ambiguous, and your best course of action would be to ask; if the drawing calls for a BS2752 neoprene, they may be offering this and the fact that they have cited the drawing number would suggest so, but given the lack of clarification and the price gap between them and Company C it would be advisable not to assume. If the drawing doesn’t specify the BS standard, then chances are they are not offering the higher grade of material.
The drawing does specify BS2751 – should I conform?
If your drawing calls for Neoprene to BS2752, there is likely to be good reason – either the environment is demanding and the performance of the gasket is key, or a commercial material has been trialled and not performed. If your budget is tight, check with the engineer or designer of the product – and if the drawing is not yours, then absolutely check with your customer before moving away from the spec; if they are happy to accept a lower grade of material then you will need a concession from them. Your supplier should ask for a concession – or at least written confirmation – before agreeing to deviate from a material stated on a drawing.
The drawing does not specify BS2751 – will a commercial material suffice?
If the drawing doesn’t call for a BS grade material then it may not be required. You should ask Company C why they have offered this; it may be that you discussed the application with them and they felt that a higher grade may be a better option, or if they were the previous supplier of this product, this may be the material that was used in manufacture on previous occasions, in which case you must consider whether you are willing to change it at this juncture. If you discussed the application with all three companies then the final judgement must be yours, but be sure that they are quoting like-for-like and were all provided with the same information. If you only want a commercial grade material, you may find that if you ask Company C for a quote in a non-BS specification, they offer an equally competitive quote or a higher quality/better lead-time; don’t dismiss any offering without ensuring that you have equivalent costings available to compare.
The product is newly designed – which option should I select?
Check the details of each material specification – there will be data sheets available. Assess the environment that the gasket it working within, the properties that you view as priorities, and talk to your suppliers – they will be able to advise you. When you ask for quotes, be clear about your requirements – and if you want to understand all available pricing options, ask for quotes in both materials. The final conclusion must be a balance between judged performance and budget – cheaper doesn’t necessarily equal cost-effective in the long term.
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